diff --git a/demo/Semi.Avalonia.Demo/Pages/DataGridDemo.axaml b/demo/Semi.Avalonia.Demo/Pages/DataGridDemo.axaml
index 44729f3..5a36e71 100644
--- a/demo/Semi.Avalonia.Demo/Pages/DataGridDemo.axaml
+++ b/demo/Semi.Avalonia.Demo/Pages/DataGridDemo.axaml
@@ -5,122 +5,95 @@
     xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
     xmlns:local="using:Semi.Avalonia.Demo.Pages"
     xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+    xmlns:vm="clr-namespace:Semi.Avalonia.Demo.ViewModels;assembly=Semi.Avalonia.Demo"
     d:DesignHeight="450"
     d:DesignWidth="800"
+    x:CompileBindings="True"
+    x:DataType="vm:DataGridDemoViewModel"
     mc:Ignorable="d">
     <TabControl>
         <TabItem Header="DataGrid">
-            <DockPanel>
-                <CheckBox
-                    x:Name="ShowGDP"
-                    Content="Toggle GDP Column Visibility"
-                    DockPanel.Dock="Top"
-                    IsChecked="True" />
-                <DataGrid
-                    Name="dataGrid1"
-                    Margin="12"
-                    CanUserReorderColumns="True"
-                    CanUserResizeColumns="True"
-                    CanUserSortColumns="True"
-                    HeadersVisibility="All">
-                    <DataGrid.Columns>
-                        <!--  Using HeaderTemplate  -->
-                        <DataGridTextColumn
-                            Width="6*"
-                            x:DataType="local:Country"
-                            Binding="{Binding Name}"
-                            Header="Country or Region" />
-                        <DataGridTextColumn
-                            Width="4*"
-                            x:DataType="local:Country"
-                            Binding="{Binding Region}"
-                            Header="Region" />
-                        <DataGridTextColumn
-                            Width="3*"
-                            x:DataType="local:Country"
-                            Binding="{Binding Population}"
-                            Header="Population" />
-                        <DataGridTextColumn
-                            Width="3*"
-                            x:DataType="local:Country"
-                            Binding="{Binding Area}"
-                            Header="Area" />
-                        <DataGridTextColumn
-                            Width="3*"
-                            MinWidth="200"
-                            x:DataType="local:Country"
-                            Binding="{Binding GDP}"
-                            Header="GDP"
-                            IsVisible="{Binding #ShowGDP.IsChecked}" />
-                    </DataGrid.Columns>
-                    <DataGrid.CellTheme>
-                        <ControlTheme BasedOn="{StaticResource {x:Type DataGridCell}}" TargetType="DataGridCell">
-                            <ControlTheme.Children>
-                                <Style Selector="^:nth-child(1)">
-                                    <Setter Property="FontWeight" Value="Bold" />
-                                </Style>
-                            </ControlTheme.Children>
-                        </ControlTheme>
-                    </DataGrid.CellTheme>
-                    <DataGrid.ColumnHeaderTheme>
-                        <ControlTheme BasedOn="{StaticResource {x:Type DataGridColumnHeader}}" TargetType="DataGridColumnHeader">
-                            <ControlTheme.Children>
-                                <Style Selector="^:nth-child(1)">
-                                    <Setter Property="FontWeight" Value="Bold" />
-                                </Style>
-                            </ControlTheme.Children>
-                        </ControlTheme>
-                    </DataGrid.ColumnHeaderTheme>
-                </DataGrid>
-            </DockPanel>
-        </TabItem>
-        <TabItem Header="Grouping">
-            <DataGrid Name="dataGridGrouping" Margin="12">
+            <DataGrid
+                Margin="8"
+                CanUserReorderColumns="True"
+                CanUserResizeColumns="True"
+                CanUserSortColumns="True"
+                HeadersVisibility="All"
+                IsReadOnly="True"
+                ItemsSource="{Binding GridData1}">
                 <DataGrid.Columns>
                     <DataGridTextColumn
                         Width="6*"
-                        x:DataType="local:Country"
-                        Binding="{Binding Name}"
-                        Header="Country or Region" />
+                        x:DataType="vm:Song"
+                        Binding="{Binding Title}"
+                        Header="Title" />
                     <DataGridTextColumn
-                        Width="4*"
-                        x:DataType="local:Country"
-                        Binding="{Binding Region}"
-                        Header="Region" />
+                        Width="6*"
+                        x:DataType="vm:Song"
+                        Binding="{Binding Artist}"
+                        Header="Artist" />
                     <DataGridTextColumn
-                        Width="3*"
-                        x:DataType="local:Country"
-                        Binding="{Binding Population}"
-                        DisplayIndex="3"
-                        Header="Population" />
-                    <DataGridTextColumn
-                        Width="3*"
-                        x:DataType="local:Country"
-                        Binding="{Binding Area}"
-                        DisplayIndex="2"
-                        Header="Area" />
-                    <DataGridTextColumn
-                        Width="3*"
-                        x:DataType="local:Country"
-                        Binding="{Binding GDP}"
-                        Header="GDP" />
+                        Width="6*"
+                        x:DataType="vm:Song"
+                        Binding="{Binding Album}"
+                        Header="Album" />
+                    <DataGridTemplateColumn Header="Duration" SortMemberPath="Duration">
+                        <DataGridTemplateColumn.CellTemplate>
+                            <DataTemplate>
+                                <TextBlock
+                                    Margin="8,0,0,0"
+                                    VerticalAlignment="Center"
+                                    Text="{Binding Duration}" />
+                            </DataTemplate>
+                        </DataGridTemplateColumn.CellTemplate>
+                    </DataGridTemplateColumn>
+                </DataGrid.Columns>
+
+            </DataGrid>
+        </TabItem>
+        <TabItem Header="Grouping">
+            <DataGrid
+                Margin="8"
+                CanUserReorderColumns="True"
+                CanUserResizeColumns="True"
+                CanUserSortColumns="True"
+                HeadersVisibility="All"
+                IsReadOnly="True"
+                ItemsSource="{Binding GridData2}">
+                <DataGrid.Columns>
+                    <DataGridTextColumn
+                        Width="6*"
+                        x:DataType="vm:Song"
+                        Binding="{Binding Title}"
+                        Header="Title" />
+                    <DataGridTextColumn
+                        Width="6*"
+                        x:DataType="vm:Song"
+                        Binding="{Binding Artist}"
+                        Header="Artist" />
+                    <DataGridTextColumn
+                        Width="6*"
+                        x:DataType="vm:Song"
+                        Binding="{Binding Album}"
+                        Header="Album" />
+                    <DataGridTemplateColumn
+                        x:DataType="vm:Song"
+                        Header="Duration"
+                        SortMemberPath="Duration">
+                        <DataGridTemplateColumn.CellTemplate>
+                            <DataTemplate x:DataType="vm:Song">
+                                <TextBlock
+                                    Margin="8,0,0,0"
+                                    VerticalAlignment="Center"
+                                    Text="{Binding Duration}" />
+                            </DataTemplate>
+                        </DataGridTemplateColumn.CellTemplate>
+                    </DataGridTemplateColumn>
                 </DataGrid.Columns>
-                <DataGrid.RowTheme>
-                    <ControlTheme BasedOn="{StaticResource {x:Type DataGridRow}}" TargetType="DataGridRow">
-                        <ControlTheme.Children>
-                            <Style Selector="^:nth-child(5n+3)">
-                                <Setter Property="Foreground" Value="Red" />
-                            </Style>
-                            <Style Selector="^:nth-last-child(5n+1)">
-                                <Setter Property="Foreground" Value="Blue" />
-                            </Style>
-                        </ControlTheme.Children>
-                    </ControlTheme>
-                </DataGrid.RowTheme>
             </DataGrid>
         </TabItem>
         <TabItem x:Name="EditableTab" Header="Editable">
-            <Grid RowDefinitions="Auto,*,Auto">
+            <Grid Margin="8" RowDefinitions="Auto,*,Auto">
                 <StackPanel
                     Grid.Row="0"
                     Orientation="Horizontal"
@@ -138,35 +111,39 @@
                         Content="IsThreeState"
                         IsChecked="False" />
                 </StackPanel>
-                <!--  Example of columns inheriting the data type from the Items source  -->
                 <DataGrid
-                    Name="dataGridEdit"
                     Grid.Row="1"
-                    Margin="12"
-                    ItemsSource="{Binding DataGrid3Source}">
+                    Margin="8"
+                    ItemsSource="{Binding GridData3}">
                     <DataGrid.Columns>
-                        <DataGridTextColumn
-                            Width="2*"
-                            Binding="{Binding FirstName}"
-                            FontSize="{Binding #FontSizeSlider.Value, Mode=OneWay}"
-                            Header="First Name" />
-                        <DataGridTextColumn
-                            Width="2*"
-                            Binding="{Binding LastName}"
-                            FontSize="{Binding #FontSizeSlider.Value, Mode=OneWay}"
-                            Header="Last" />
                         <DataGridCheckBoxColumn
-                            Width="*"
-                            Binding="{Binding IsBanned}"
-                            Header="Is Banned"
+                            Width="2*"
+                            Binding="{Binding IsSelected}"
+                            Header="Select"
                             IsThreeState="{Binding #IsThreeStateCheckBox.IsChecked, Mode=OneWay}" />
-                        <DataGridTemplateColumn Header="Age">
+                        <DataGridTextColumn
+                            Width="6*"
+                            x:DataType="vm:SongViewModel"
+                            Binding="{Binding Title}"
+                            FontSize="{Binding #FontSizeSlider.Value, Mode=OneWay}"
+                            Header="Title" />
+                        <DataGridTextColumn
+                            Width="6*"
+                            x:DataType="vm:SongViewModel"
+                            Binding="{Binding Artist}"
+                            Header="Artist" />
+                        <DataGridTextColumn
+                            Width="6*"
+                            x:DataType="vm:SongViewModel"
+                            Binding="{Binding Album}"
+                            Header="Album" />
+                        <DataGridTemplateColumn Width="2*" Header="Comments">
                             <DataGridTemplateColumn.CellTemplate>
                                 <DataTemplate>
                                     <TextBlock
                                         HorizontalAlignment="Center"
                                         VerticalAlignment="Center"
-                                        Text="{Binding Age, StringFormat='{}{0} years'}" />
+                                        Text="{Binding CountOfComment}" />
                                 </DataTemplate>
                             </DataGridTemplateColumn.CellTemplate>
                             <DataGridTemplateColumn.CellEditingTemplate>
@@ -174,17 +151,14 @@
                                     <NumericUpDown
                                         HorizontalAlignment="Stretch"
                                         FormatString="N0"
-                                        Maximum="120"
                                         Minimum="0"
-                                        TemplateApplied="NumericUpDown_OnTemplateApplied"
-                                        Value="{Binding Age}" />
+                                        Value="{Binding CountOfComment}" />
                                 </DataTemplate>
                             </DataGridTemplateColumn.CellEditingTemplate>
                         </DataGridTemplateColumn>
                     </DataGrid.Columns>
                 </DataGrid>
                 <Button
-                    Name="btnAdd"
                     Grid.Row="2"
                     Margin="12,0,12,12"
                     HorizontalAlignment="Right"
diff --git a/demo/Semi.Avalonia.Demo/Pages/DataGridDemo.axaml.cs b/demo/Semi.Avalonia.Demo/Pages/DataGridDemo.axaml.cs
index f6fd52d..7af3eb8 100644
--- a/demo/Semi.Avalonia.Demo/Pages/DataGridDemo.axaml.cs
+++ b/demo/Semi.Avalonia.Demo/Pages/DataGridDemo.axaml.cs
@@ -13,6 +13,7 @@ using Avalonia.Input;
 using Avalonia.Input.Raw;
 using Avalonia.Markup.Xaml;
 using Avalonia.Threading;
+using Semi.Avalonia.Demo.ViewModels;
 
 namespace Semi.Avalonia.Demo.Pages;
 
@@ -21,488 +22,6 @@ public partial class DataGridDemo : UserControl
     public DataGridDemo()
     {
         InitializeComponent();
-        var dataGridSortDescription = DataGridSortDescription.FromPath(nameof(Country.Region), ListSortDirection.Ascending, new ReversedStringComparer());
-        var collectionView1 = new DataGridCollectionView(Countries.All);
-        collectionView1.SortDescriptions.Add(dataGridSortDescription);
-        var dg1 = this.Get<DataGrid>("dataGrid1");
-        dg1.IsReadOnly = true;
-        dg1.LoadingRow += Dg1_LoadingRow;
-        dg1.Sorting += (s, a) =>
-        {
-            var binding = (a.Column as DataGridBoundColumn)?.Binding as Binding;
-
-            if (binding?.Path is string property
-                && property == dataGridSortDescription.PropertyPath
-                && !collectionView1.SortDescriptions.Contains(dataGridSortDescription))
-            {
-                collectionView1.SortDescriptions.Add(dataGridSortDescription);
-            }
-        };
-        dg1.ItemsSource = collectionView1;
-
-        var dg2 = this.Get<DataGrid>("dataGridGrouping");
-        dg2.IsReadOnly = true;
-
-        var collectionView2 = new DataGridCollectionView(Countries.All);
-        collectionView2.GroupDescriptions.Add(new DataGridPathGroupDescription("Region"));
-
-        dg2.ItemsSource = collectionView2;
-
-        var dg3 = this.Get<DataGrid>("dataGridEdit");
-        dg3.IsReadOnly = false;
-
-        var list = new ObservableCollection<Person>
-        {
-            new Person { FirstName = "John", LastName = "Doe" , Age = 30},
-            new Person { FirstName = "Elizabeth", LastName = "Thomas", IsBanned = true , Age = 40 },
-            new Person { FirstName = "Zack", LastName = "Ward" , Age = 50 }
-        };
-        DataGrid3Source = list;
-
-        var addButton = this.Get<Button>("btnAdd");
-        addButton.Click += (a, b) => list.Add(new Person());
-
-        DataContext = this;
-    }
-    
-    public IEnumerable<Person> DataGrid3Source { get; }
-        
-    private void Dg1_LoadingRow(object? sender, DataGridRowEventArgs e)
-    {
-        e.Row.Header = e.Row.GetIndex() + 1;
-    }
-
-    private void InitializeComponent()
-    {
-        AvaloniaXamlLoader.Load(this);
-    }
-
-    private class ReversedStringComparer : IComparer<object>, IComparer
-    {
-        public int Compare(object? x, object? y)
-        {
-            if (x is string left && y is string right)
-            {
-                var reversedLeft = new string(left.Reverse().ToArray());
-                var reversedRight = new string(right.Reverse().ToArray());
-                return reversedLeft.CompareTo(reversedRight);
-            }
-
-            return Comparer.Default.Compare(x, y);
-        }
-    }
-
-    private void NumericUpDown_OnTemplateApplied(object sender, TemplateAppliedEventArgs e)
-    {
-        // We want to focus the TextBox of the NumericUpDown. To do so we search for this control when the template
-        // is applied, but we postpone the action until the control is actually loaded. 
-        if (e.NameScope.Find<TextBox>("PART_TextBox") is {} textBox)
-        {
-            Dispatcher.UIThread.InvokeAsync(() =>
-            {
-                textBox.Focus();
-                textBox.SelectAll();
-            }, DispatcherPriority.Loaded);
-        }
-    }
-}
-
-public class Person : INotifyDataErrorInfo, INotifyPropertyChanged
-    {
-        string _firstName = string.Empty;
-        string _lastName = string.Empty;
-        bool _isBanned;
-        private int _age;
-
-        public string FirstName
-        {
-            get => _firstName;
-            set
-            {
-                _firstName = value;
-                if (string.IsNullOrWhiteSpace(value))
-                    SetError(nameof(FirstName), "First Name Required");
-                else
-                    SetError(nameof(FirstName), null);
-
-                OnPropertyChanged(nameof(FirstName));
-            }
-
-        }
-
-        public string LastName
-        {
-            get => _lastName;
-            set
-            {
-                _lastName = value;
-                if (string.IsNullOrWhiteSpace(value))
-                    SetError(nameof(LastName), "Last Name Required");
-                else
-                    SetError(nameof(LastName), null);
-
-                OnPropertyChanged(nameof(LastName));
-            }
-        }
-
-        public bool IsBanned
-        {
-            get => _isBanned;
-            set
-            {
-                _isBanned = value;
-
-                OnPropertyChanged(nameof(_isBanned));
-            }
-        }
-
-        
-        /// <summary>
-        ///    Gets or sets the age of the person
-        /// </summary>
-        public int Age
-        {
-            get => _age;
-            set
-            {
-                _age = value;
-                OnPropertyChanged(nameof(Age));
-            }
-        }
-
-        Dictionary<string, List<string>> _errorLookup = new Dictionary<string, List<string>>();
-
-        void SetError(string propertyName, string? error)
-        {
-            if (string.IsNullOrEmpty(error))
-            {
-                if (_errorLookup.Remove(propertyName))
-                    OnErrorsChanged(propertyName);
-            }
-            else
-            {
-                if (_errorLookup.TryGetValue(propertyName, out var errorList))
-                {
-                    errorList.Clear();
-                    errorList.Add(error!);
-                }
-                else
-                {
-                    var errors = new List<string> { error! };
-                    _errorLookup.Add(propertyName, errors);
-                }
-
-                OnErrorsChanged(propertyName);
-            }
-        }
-
-        public bool HasErrors => _errorLookup.Count > 0;
-
-        public event EventHandler<DataErrorsChangedEventArgs>? ErrorsChanged;
-        public event PropertyChangedEventHandler? PropertyChanged;
-
-        void OnErrorsChanged(string propertyName)
-        {
-            ErrorsChanged?.Invoke(this, new DataErrorsChangedEventArgs(propertyName));
-        }
-        void OnPropertyChanged(string propertyName)
-        {
-            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
-        }
-
-        public IEnumerable GetErrors(string? propertyName)
-        {
-            if (propertyName is { } && _errorLookup.TryGetValue(propertyName, out var errorList))
-                return errorList;
-            else
-                return Array.Empty<object>();
-        }
-    }
-    
-    public static class Countries
-    {
-        static IEnumerable<Country> GetCountries()
-        {
-            yield return new Country("Afghanistan", "ASIA (EX. NEAR EAST)", 31056997, 647500, 48, 0, 23.06, 163.07, 700, 36, 3.2, 46.6, 20.34);
-            yield return new Country("Albania", "EASTERN EUROPE", 3581655, 28748, 124.6, 1.26, -4.93, 21.52, 4500, 86.5, 71.2, 15.11, 5.22);
-            yield return new Country("Algeria", "NORTHERN AFRICA", 32930091, 2381740, 13.8, 0.04, -0.39, 31, 6000, 70, 78.1, 17.14, 4.61);
-            yield return new Country("American Samoa", "OCEANIA", 57794, 199, 290.4, 58.29, -20.71, 9.27, 8000, 97, 259.5, 22.46, 3.27);
-            yield return new Country("Andorra", "WESTERN EUROPE", 71201, 468, 152.1, 0, 6.6, 4.05, 19000, 100, 497.2, 8.71, 6.25);
-            yield return new Country("Angola", "SUB-SAHARAN AFRICA", 12127071, 1246700, 9.7, 0.13, 0, 191.19, 1900, 42, 7.8, 45.11, 24.2);
-            yield return new Country("Anguilla", "LATIN AMER. & CARIB", 13477, 102, 132.1, 59.8, 10.76, 21.03, 8600, 95, 460, 14.17, 5.34);
-            yield return new Country("Antigua & Barbuda", "LATIN AMER. & CARIB", 69108, 443, 156, 34.54, -6.15, 19.46, 11000, 89, 549.9, 16.93, 5.37);
-            yield return new Country("Argentina", "LATIN AMER. & CARIB", 39921833, 2766890, 14.4, 0.18, 0.61, 15.18, 11200, 97.1, 220.4, 16.73, 7.55);
-            yield return new Country("Armenia", "C.W. OF IND. STATES", 2976372, 29800, 99.9, 0, -6.47, 23.28, 3500, 98.6, 195.7, 12.07, 8.23);
-            yield return new Country("Aruba", "LATIN AMER. & CARIB", 71891, 193, 372.5, 35.49, 0, 5.89, 28000, 97, 516.1, 11.03, 6.68);
-            yield return new Country("Australia", "OCEANIA", 20264082, 7686850, 2.6, 0.34, 3.98, 4.69, 29000, 100, 565.5, 12.14, 7.51);
-            yield return new Country("Austria", "WESTERN EUROPE", 8192880, 83870, 97.7, 0, 2, 4.66, 30000, 98, 452.2, 8.74, 9.76);
-            yield return new Country("Azerbaijan", "C.W. OF IND. STATES", 7961619, 86600, 91.9, 0, -4.9, 81.74, 3400, 97, 137.1, 20.74, 9.75);
-            yield return new Country("The Bahamas", "LATIN AMER. & CARIB", 303770, 13940, 21.8, 25.41, -2.2, 25.21, 16700, 95.6, 460.6, 17.57, 9.05);
-            yield return new Country("Bahrain", "NEAR EAST", 698585, 665, 1050.5, 24.21, 1.05, 17.27, 16900, 89.1, 281.3, 17.8, 4.14);
-            yield return new Country("Bangladesh", "ASIA (EX. NEAR EAST)", 147365352, 144000, 1023.4, 0.4, -0.71, 62.6, 1900, 43.1, 7.3, 29.8, 8.27);
-            yield return new Country("Barbados", "LATIN AMER. & CARIB", 279912, 431, 649.5, 22.51, -0.31, 12.5, 15700, 97.4, 481.9, 12.71, 8.67);
-            yield return new Country("Belarus", "C.W. OF IND. STATES", 10293011, 207600, 49.6, 0, 2.54, 13.37, 6100, 99.6, 319.1, 11.16, 14.02);
-            yield return new Country("Belgium", "WESTERN EUROPE", 10379067, 30528, 340, 0.22, 1.23, 4.68, 29100, 98, 462.6, 10.38, 10.27);
-            yield return new Country("Belize", "LATIN AMER. & CARIB", 287730, 22966, 12.5, 1.68, 0, 25.69, 4900, 94.1, 115.7, 28.84, 5.72);
-            yield return new Country("Benin", "SUB-SAHARAN AFRICA", 7862944, 112620, 69.8, 0.11, 0, 85, 1100, 40.9, 9.7, 38.85, 12.22);
-            yield return new Country("Bermuda", "NORTHERN AMERICA", 65773, 53, 1241, 194.34, 2.49, 8.53, 36000, 98, 851.4, 11.4, 7.74);
-            yield return new Country("Bhutan", "ASIA (EX. NEAR EAST)", 2279723, 47000, 48.5, 0, 0, 100.44, 1300, 42.2, 14.3, 33.65, 12.7);
-            yield return new Country("Bolivia", "LATIN AMER. & CARIB", 8989046, 1098580, 8.2, 0, -1.32, 53.11, 2400, 87.2, 71.9, 23.3, 7.53);
-            yield return new Country("Bosnia & Herzegovina", "EASTERN EUROPE", 4498976, 51129, 88, 0.04, 0.31, 21.05, 6100,null, 215.4, 8.77, 8.27);
-            yield return new Country("Botswana", "SUB-SAHARAN AFRICA", 1639833, 600370, 2.7, 0, 0, 54.58, 9000, 79.8, 80.5, 23.08, 29.5);
-            yield return new Country("Brazil", "LATIN AMER. & CARIB", 188078227, 8511965, 22.1, 0.09, -0.03, 29.61, 7600, 86.4, 225.3, 16.56, 6.17);
-            yield return new Country("British Virgin Is.", "LATIN AMER. & CARIB", 23098, 153, 151, 52.29, 10.01, 18.05, 16000, 97.8, 506.5, 14.89, 4.42);
-            yield return new Country("Brunei", "ASIA (EX. NEAR EAST)", 379444, 5770, 65.8, 2.79, 3.59, 12.61, 18600, 93.9, 237.2, 18.79, 3.45);
-            yield return new Country("Bulgaria", "EASTERN EUROPE", 7385367, 110910, 66.6, 0.32, -4.58, 20.55, 7600, 98.6, 336.3, 9.65, 14.27);
-            yield return new Country("Burkina Faso", "SUB-SAHARAN AFRICA", 13902972, 274200, 50.7, 0, 0, 97.57, 1100, 26.6, 7, 45.62, 15.6);
-            yield return new Country("Burma", "ASIA (EX. NEAR EAST)", 47382633, 678500, 69.8, 0.28, -1.8, 67.24, 1800, 85.3, 10.1, 17.91, 9.83);
-            yield return new Country("Burundi", "SUB-SAHARAN AFRICA", 8090068, 27830, 290.7, 0, -0.06, 69.29, 600, 51.6, 3.4, 42.22, 13.46);
-            yield return new Country("Cambodia", "ASIA (EX. NEAR EAST)", 13881427, 181040, 76.7, 0.24, 0, 71.48, 1900, 69.4, 2.6, 26.9, 9.06);
-            yield return new Country("Cameroon", "SUB-SAHARAN AFRICA", 17340702, 475440, 36.5, 0.08, 0, 68.26, 1800, 79, 5.7, 33.89, 13.47);
-            yield return new Country("Canada", "NORTHERN AMERICA", 33098932, 9984670, 3.3, 2.02, 5.96, 4.75, 29800, 97, 552.2, 10.78, 7.8);
-            yield return new Country("Cape Verde", "SUB-SAHARAN AFRICA", 420979, 4033, 104.4, 23.93, -12.07, 47.77, 1400, 76.6, 169.6, 24.87, 6.55);
-            yield return new Country("Cayman Islands", "LATIN AMER. & CARIB", 45436, 262, 173.4, 61.07, 18.75, 8.19, 35000, 98, 836.3, 12.74, 4.89);
-            yield return new Country("Central African Rep.", "SUB-SAHARAN AFRICA", 4303356, 622984, 6.9, 0, 0, 91, 1100, 51, 2.3, 33.91, 18.65);
-            yield return new Country("Chad", "SUB-SAHARAN AFRICA", 9944201, 1284000, 7.7, 0, -0.11, 93.82, 1200, 47.5, 1.3, 45.73, 16.38);
-            yield return new Country("Chile", "LATIN AMER. & CARIB", 16134219, 756950, 21.3, 0.85, 0, 8.8, 9900, 96.2, 213, 15.23, 5.81);
-            yield return new Country("China", "ASIA (EX. NEAR EAST)", 1313973713, 9596960, 136.9, 0.15, -0.4, 24.18, 5000, 90.9, 266.7, 13.25, 6.97);
-            yield return new Country("Colombia", "LATIN AMER. & CARIB", 43593035, 1138910, 38.3, 0.28, -0.31, 20.97, 6300, 92.5, 176.2, 20.48, 5.58);
-            yield return new Country("Comoros", "SUB-SAHARAN AFRICA", 690948, 2170, 318.4, 15.67, 0, 74.93, 700, 56.5, 24.5, 36.93, 8.2);
-            yield return new Country("Congo, Dem.Rep.", "SUB - SAHARAN AFRICA", 62660551, 2345410, 26.7, 0, 0, 94.69, 700, 65.5, 0.2, 43.69, 13.27);
-            yield return new Country("Congo, Repub.of the", "SUB - SAHARAN AFRICA", 3702314, 342000, 10.8, 0.05, -0.17, 93.86, 700, 83.8, 3.7, 42.57, 12.93);
-            yield return new Country("Cook Islands", "OCEANIA", 21388, 240, 89.1, 50,null,null, 5000, 95, 289.9, 21,null);
-            yield return new Country("Costa Rica", "LATIN AMER. & CARIB", 4075261, 51100, 79.8, 2.52, 0.51, 9.95, 9100, 96, 340.7, 18.32, 4.36);
-            yield return new Country("Cote d'Ivoire", "SUB-SAHARAN AFRICA", 17654843, 322460, 54.8, 0.16, -0.07, 90.83, 1400, 50.9, 14.6, 35.11, 14.84);
-            yield return new Country("Croatia", "EASTERN EUROPE", 4494749, 56542, 79.5, 10.32, 1.58, 6.84, 10600, 98.5, 420.4, 9.61, 11.48);
-            yield return new Country("Cuba", "LATIN AMER. & CARIB", 11382820, 110860, 102.7, 3.37, -1.58, 6.33, 2900, 97, 74.7, 11.89, 7.22);
-            yield return new Country("Cyprus", "NEAR EAST", 784301, 9250, 84.8, 7.01, 0.43, 7.18, 19200, 97.6,null, 12.56, 7.68);
-            yield return new Country("Czech Republic", "EASTERN EUROPE", 10235455, 78866, 129.8, 0, 0.97, 3.93, 15700, 99.9, 314.3, 9.02, 10.59);
-            yield return new Country("Denmark", "WESTERN EUROPE", 5450661, 43094, 126.5, 16.97, 2.48, 4.56, 31100, 100, 614.6, 11.13, 10.36);
-            yield return new Country("Djibouti", "SUB-SAHARAN AFRICA", 486530, 23000, 21.2, 1.37, 0, 104.13, 1300, 67.9, 22.8, 39.53, 19.31);
-            yield return new Country("Dominica", "LATIN AMER. & CARIB", 68910, 754, 91.4, 19.63, -13.87, 14.15, 5400, 94, 304.8, 15.27, 6.73);
-            yield return new Country("Dominican Republic", "LATIN AMER. & CARIB", 9183984, 48730, 188.5, 2.64, -3.22, 32.38, 6000, 84.7, 97.4, 23.22, 5.73);
-            yield return new Country("East Timor", "ASIA (EX. NEAR EAST)", 1062777, 15007, 70.8, 4.7, 0, 47.41, 500, 58.6,null, 26.99, 6.24);
-            yield return new Country("Ecuador", "LATIN AMER. & CARIB", 13547510, 283560, 47.8, 0.79, -8.58, 23.66, 3300, 92.5, 125.6, 22.29, 4.23);
-            yield return new Country("Egypt", "NORTHERN AFRICA", 78887007, 1001450, 78.8, 0.24, -0.22, 32.59, 4000, 57.7, 131.8, 22.94, 5.23);
-            yield return new Country("El Salvador", "LATIN AMER. & CARIB", 6822378, 21040, 324.3, 1.46, -3.74, 25.1, 4800, 80.2, 142.4, 26.61, 5.78);
-            yield return new Country("Equatorial Guinea", "SUB-SAHARAN AFRICA", 540109, 28051, 19.3, 1.06, 0, 85.13, 2700, 85.7, 18.5, 35.59, 15.06);
-            yield return new Country("Eritrea", "SUB-SAHARAN AFRICA", 4786994, 121320, 39.5, 1.84, 0, 74.87, 700, 58.6, 7.9, 34.33, 9.6);
-            yield return new Country("Estonia", "BALTICS", 1324333, 45226, 29.3, 8.39, -3.16, 7.87, 12300, 99.8, 333.8, 10.04, 13.25);
-            yield return new Country("Ethiopia", "SUB-SAHARAN AFRICA", 74777981, 1127127, 66.3, 0, 0, 95.32, 700, 42.7, 8.2, 37.98, 14.86);
-            yield return new Country("Faroe Islands", "WESTERN EUROPE", 47246, 1399, 33.8, 79.84, 1.41, 6.24, 22000,null, 503.8, 14.05, 8.7);
-            yield return new Country("Fiji", "OCEANIA", 905949, 18270, 49.6, 6.18, -3.14, 12.62, 5800, 93.7, 112.6, 22.55, 5.65);
-            yield return new Country("Finland", "WESTERN EUROPE", 5231372, 338145, 15.5, 0.37, 0.95, 3.57, 27400, 100, 405.3, 10.45, 9.86);
-            yield return new Country("France", "WESTERN EUROPE", 60876136, 547030, 111.3, 0.63, 0.66, 4.26, 27600, 99, 586.4, 11.99, 9.14);
-            yield return new Country("French Guiana", "LATIN AMER. & CARIB", 199509, 91000, 2.2, 0.42, 6.27, 12.07, 8300, 83, 255.6, 20.46, 4.88);
-            yield return new Country("French Polynesia", "OCEANIA", 274578, 4167, 65.9, 60.6, 2.94, 8.44, 17500, 98, 194.5, 16.68, 4.69);
-            yield return new Country("Gabon", "SUB-SAHARAN AFRICA", 1424906, 267667, 5.3, 0.33, 0, 53.64, 5500, 63.2, 27.4, 36.16, 12.25);
-            yield return new Country("Gambia, The", "SUB - SAHARAN AFRICA", 1641564, 11300, 145.3, 0.71, 1.57, 72.02, 1700, 40.1, 26.8, 39.37, 12.25);
-            yield return new Country("Gaza Strip", "NEAR EAST", 1428757, 360, 3968.8, 11.11, 1.6, 22.93, 600,null, 244.3, 39.45, 3.8);
-            yield return new Country("Georgia", "C.W. OF IND. STATES", 4661473, 69700, 66.9, 0.44, -4.7, 18.59, 2500, 99, 146.6, 10.41, 9.23);
-            yield return new Country("Germany", "WESTERN EUROPE", 82422299, 357021, 230.9, 0.67, 2.18, 4.16, 27600, 99, 667.9, 8.25, 10.62);
-            yield return new Country("Ghana", "SUB-SAHARAN AFRICA", 22409572, 239460, 93.6, 0.23, -0.64, 51.43, 2200, 74.8, 14.4, 30.52, 9.72);
-            yield return new Country("Gibraltar", "WESTERN EUROPE", 27928, 7, 3989.7, 171.43, 0, 5.13, 17500,null, 877.7, 10.74, 9.31);
-            yield return new Country("Greece", "WESTERN EUROPE", 10688058, 131940, 81, 10.37, 2.35, 5.53, 20000, 97.5, 589.7, 9.68, 10.24);
-            yield return new Country("Greenland", "NORTHERN AMERICA", 56361, 2166086, 0, 2.04, -8.37, 15.82, 20000,null, 448.9, 15.93, 7.84);
-            yield return new Country("Grenada", "LATIN AMER. & CARIB", 89703, 344, 260.8, 35.17, -13.92, 14.62, 5000, 98, 364.5, 22.08, 6.88);
-            yield return new Country("Guadeloupe", "LATIN AMER. & CARIB", 452776, 1780, 254.4, 17.19, -0.15, 8.6, 8000, 90, 463.8, 15.05, 6.09);
-            yield return new Country("Guam", "OCEANIA", 171019, 541, 316.1, 23.2, 0, 6.94, 21000, 99, 492, 18.79, 4.48);
-            yield return new Country("Guatemala", "LATIN AMER. & CARIB", 12293545, 108890, 112.9, 0.37, -1.67, 35.93, 4100, 70.6, 92.1, 29.88, 5.2);
-            yield return new Country("Guernsey", "WESTERN EUROPE", 65409, 78, 838.6, 64.1, 3.84, 4.71, 20000,null, 842.4, 8.81, 10.01);
-            yield return new Country("Guinea", "SUB-SAHARAN AFRICA", 9690222, 245857, 39.4, 0.13, -3.06, 90.37, 2100, 35.9, 2.7, 41.76, 15.48);
-            yield return new Country("Guinea-Bissau", "SUB-SAHARAN AFRICA", 1442029, 36120, 39.9, 0.97, -1.57, 107.17, 800, 42.4, 7.4, 37.22, 16.53);
-            yield return new Country("Guyana", "LATIN AMER. & CARIB", 767245, 214970, 3.6, 0.21, -2.07, 33.26, 4000, 98.8, 143.5, 18.28, 8.28);
-            yield return new Country("Haiti", "LATIN AMER. & CARIB", 8308504, 27750, 299.4, 6.38, -3.4, 73.45, 1600, 52.9, 16.9, 36.44, 12.17);
-            yield return new Country("Honduras", "LATIN AMER. & CARIB", 7326496, 112090, 65.4, 0.73, -1.99, 29.32, 2600, 76.2, 67.5, 28.24, 5.28);
-            yield return new Country("Hong Kong", "ASIA (EX. NEAR EAST)", 6940432, 1092, 6355.7, 67.12, 5.24, 2.97, 28800, 93.5, 546.7, 7.29, 6.29);
-            yield return new Country("Hungary", "EASTERN EUROPE", 9981334, 93030, 107.3, 0, 0.86, 8.57, 13900, 99.4, 336.2, 9.72, 13.11);
-            yield return new Country("Iceland", "WESTERN EUROPE", 299388, 103000, 2.9, 4.83, 2.38, 3.31, 30900, 99.9, 647.7, 13.64, 6.72);
-            yield return new Country("India", "ASIA (EX. NEAR EAST)", 1095351995, 3287590, 333.2, 0.21, -0.07, 56.29, 2900, 59.5, 45.4, 22.01, 8.18);
-            yield return new Country("Indonesia", "ASIA (EX. NEAR EAST)", 245452739, 1919440, 127.9, 2.85, 0, 35.6, 3200, 87.9, 52, 20.34, 6.25);
-            yield return new Country("Iran", "ASIA (EX. NEAR EAST)", 68688433, 1648000, 41.7, 0.15, -0.84, 41.58, 7000, 79.4, 276.4, 17, 5.55);
-            yield return new Country("Iraq", "NEAR EAST", 26783383, 437072, 61.3, 0.01, 0, 50.25, 1500, 40.4, 38.6, 31.98, 5.37);
-            yield return new Country("Ireland", "WESTERN EUROPE", 4062235, 70280, 57.8, 2.06, 4.99, 5.39, 29600, 98, 500.5, 14.45, 7.82);
-            yield return new Country("Isle of Man", "WESTERN EUROPE", 75441, 572, 131.9, 27.97, 5.36, 5.93, 21000,null, 676, 11.05, 11.19);
-            yield return new Country("Israel", "NEAR EAST", 6352117, 20770, 305.8, 1.31, 0.68, 7.03, 19800, 95.4, 462.3, 17.97, 6.18);
-            yield return new Country("Italy", "WESTERN EUROPE", 58133509, 301230, 193, 2.52, 2.07, 5.94, 26700, 98.6, 430.9, 8.72, 10.4);
-            yield return new Country("Jamaica", "LATIN AMER. & CARIB", 2758124, 10991, 250.9, 9.3, -4.92, 12.36, 3900, 87.9, 124, 20.82, 6.52);
-            yield return new Country("Japan", "ASIA (EX. NEAR EAST)", 127463611, 377835, 337.4, 7.87, 0, 3.26, 28200, 99, 461.2, 9.37, 9.16);
-            yield return new Country("Jersey", "WESTERN EUROPE", 91084, 116, 785.2, 60.34, 2.76, 5.24, 24800,null, 811.3, 9.3, 9.28);
-            yield return new Country("Jordan", "NEAR EAST", 5906760, 92300, 64, 0.03, 6.59, 17.35, 4300, 91.3, 104.5, 21.25, 2.65);
-            yield return new Country("Kazakhstan", "C.W. OF IND. STATES", 15233244, 2717300, 5.6, 0, -3.35, 29.21, 6300, 98.4, 164.1, 16, 9.42);
-            yield return new Country("Kenya", "SUB-SAHARAN AFRICA", 34707817, 582650, 59.6, 0.09, -0.1, 61.47, 1000, 85.1, 8.1, 39.72, 14.02);
-            yield return new Country("Kiribati", "OCEANIA", 105432, 811, 130, 140.94, 0, 48.52, 800,null, 42.7, 30.65, 8.26);
-            yield return new Country("North Korea", "ASIA(EX.NEAR EAST)", 23113019, 120540, 191.8, 2.07, 0, 24.04, 1300, 99, 42.4, 15.54, 7.13);
-            yield return new Country("South Korea", "ASIA(EX.NEAR EAST)", 48846823, 98480, 496, 2.45, 0, 7.05, 17800, 97.9, 486.1, 10, 5.85);
-            yield return new Country("Kuwait", "NEAR EAST", 2418393, 17820, 135.7, 2.8, 14.18, 9.95, 19000, 83.5, 211, 21.94, 2.41);
-            yield return new Country("Kyrgyzstan", "C.W. OF IND. STATES", 5213898, 198500, 26.3, 0, -2.45, 35.64, 1600, 97, 84, 22.8, 7.08);
-            yield return new Country("Laos", "ASIA (EX. NEAR EAST)", 6368481, 236800, 26.9, 0, 0, 85.22, 1700, 66.4, 14.1, 35.49, 11.55);
-            yield return new Country("Latvia", "BALTICS", 2274735, 64589, 35.2, 0.82, -2.23, 9.55, 10200, 99.8, 321.4, 9.24, 13.66);
-            yield return new Country("Lebanon", "NEAR EAST", 3874050, 10400, 372.5, 2.16, 0, 24.52, 4800, 87.4, 255.6, 18.52, 6.21);
-            yield return new Country("Lesotho", "SUB-SAHARAN AFRICA", 2022331, 30355, 66.6, 0, -0.74, 84.23, 3000, 84.8, 23.7, 24.75, 28.71);
-            yield return new Country("Liberia", "SUB-SAHARAN AFRICA", 3042004, 111370, 27.3, 0.52, 0, 128.87, 1000, 57.5, 2.3, 44.77, 23.1);
-            yield return new Country("Libya", "NORTHERN AFRICA", 5900754, 1759540, 3.4, 0.1, 0, 24.6, 6400, 82.6, 127.1, 26.49, 3.48);
-            yield return new Country("Liechtenstein", "WESTERN EUROPE", 33987, 160, 212.4, 0, 4.85, 4.7, 25000, 100, 585.5, 10.21, 7.18);
-            yield return new Country("Lithuania", "BALTICS", 3585906, 65200, 55, 0.14, -0.71, 6.89, 11400, 99.6, 223.4, 8.75, 10.98);
-            yield return new Country("Luxembourg", "WESTERN EUROPE", 474413, 2586, 183.5, 0, 8.97, 4.81, 55100, 100, 515.4, 11.94, 8.41);
-            yield return new Country("Macau", "ASIA (EX. NEAR EAST)", 453125, 28, 16183, 146.43, 4.86, 4.39, 19400, 94.5, 384.9, 8.48, 4.47);
-            yield return new Country("Macedonia", "EASTERN EUROPE", 2050554, 25333, 80.9, 0, -1.45, 10.09, 6700,null, 260, 12.02, 8.77);
-            yield return new Country("Madagascar", "SUB-SAHARAN AFRICA", 18595469, 587040, 31.7, 0.82, 0, 76.83, 800, 68.9, 3.6, 41.41, 11.11);
-            yield return new Country("Malawi", "SUB-SAHARAN AFRICA", 13013926, 118480, 109.8, 0, 0, 103.32, 600, 62.7, 7.9, 43.13, 19.33);
-            yield return new Country("Malaysia", "ASIA (EX. NEAR EAST)", 24385858, 329750, 74, 1.42, 0, 17.7, 9000, 88.7, 179, 22.86, 5.05);
-            yield return new Country("Maldives", "ASIA (EX. NEAR EAST)", 359008, 300, 1196.7, 214.67, 0, 56.52, 3900, 97.2, 90, 34.81, 7.06);
-            yield return new Country("Mali", "SUB-SAHARAN AFRICA", 11716829, 1240000, 9.5, 0, -0.33, 116.79, 900, 46.4, 6.4, 49.82, 16.89);
-            yield return new Country("Malta", "WESTERN EUROPE", 400214, 316, 1266.5, 62.28, 2.07, 3.89, 17700, 92.8, 505, 10.22, 8.1);
-            yield return new Country("Marshall Islands", "OCEANIA", 60422, 11854, 5.1, 3.12, -6.04, 29.45, 1600, 93.7, 91.2, 33.05, 4.78);
-            yield return new Country("Martinique", "LATIN AMER. & CARIB", 436131, 1100, 396.5, 31.82, -0.05, 7.09, 14400, 97.7, 394.4, 13.74, 6.48);
-            yield return new Country("Mauritania", "SUB-SAHARAN AFRICA", 3177388, 1030700, 3.1, 0.07, 0, 70.89, 1800, 41.7, 12.9, 40.99, 12.16);
-            yield return new Country("Mauritius", "SUB-SAHARAN AFRICA", 1240827, 2040, 608.3, 8.68, -0.9, 15.03, 11400, 85.6, 289.3, 15.43, 6.86);
-            yield return new Country("Mayotte", "SUB-SAHARAN AFRICA", 201234, 374, 538.1, 49.52, 6.78, 62.4, 2600,null, 49.7, 40.95, 7.7);
-            yield return new Country("Mexico", "LATIN AMER. & CARIB", 107449525, 1972550, 54.5, 0.47, -4.87, 20.91, 9000, 92.2, 181.6, 20.69, 4.74);
-            yield return new Country("Micronesia, Fed.St.", "OCEANIA", 108004, 702, 153.9, 870.66, -20.99, 30.21, 2000, 89, 114.8, 24.68, 4.75);
-            yield return new Country("Moldova", "C.W. OF IND. STATES", 4466706, 33843, 132, 0, -0.26, 40.42, 1800, 99.1, 208.1, 15.7, 12.64);
-            yield return new Country("Monaco", "WESTERN EUROPE", 32543, 2, 16271.5, 205, 7.75, 5.43, 27000, 99, 1035.6, 9.19, 12.91);
-            yield return new Country("Mongolia", "ASIA (EX. NEAR EAST)", 2832224, 1564116, 1.8, 0, 0, 53.79, 1800, 97.8, 55.1, 21.59, 6.95);
-            yield return new Country("Montserrat", "LATIN AMER. & CARIB", 9439, 102, 92.5, 39.22, 0, 7.35, 3400, 97,null, 17.59, 7.1);
-            yield return new Country("Morocco", "NORTHERN AFRICA", 33241259, 446550, 74.4, 0.41, -0.98, 41.62, 4000, 51.7, 40.4, 21.98, 5.58);
-            yield return new Country("Mozambique", "SUB-SAHARAN AFRICA", 19686505, 801590, 24.6, 0.31, 0, 130.79, 1200, 47.8, 3.5, 35.18, 21.35);
-            yield return new Country("Namibia", "SUB-SAHARAN AFRICA", 2044147, 825418, 2.5, 0.19, 0, 48.98, 7200, 84, 62.6, 24.32, 18.86);
-            yield return new Country("Nauru", "OCEANIA", 13287, 21, 632.7, 142.86, 0, 9.95, 5000,null, 143, 24.76, 6.7);
-            yield return new Country("Nepal", "ASIA (EX. NEAR EAST)", 28287147, 147181, 192.2, 0, 0, 66.98, 1400, 45.2, 15.9, 30.98, 9.31);
-            yield return new Country("Netherlands", "WESTERN EUROPE", 16491461, 41526, 397.1, 1.09, 2.91, 5.04, 28600, 99, 460.8, 10.9, 8.68);
-            yield return new Country("Netherlands Antilles", "LATIN AMER. & CARIB", 221736, 960, 231, 37.92, -0.41, 10.03, 11400, 96.7, 365.3, 14.78, 6.45);
-            yield return new Country("New Caledonia", "OCEANIA", 219246, 19060, 11.5, 11.83, 0, 7.72, 15000, 91, 252.2, 18.11, 5.69);
-            yield return new Country("New Zealand", "OCEANIA", 4076140, 268680, 15.2, 5.63, 4.05, 5.85, 21600, 99, 441.7, 13.76, 7.53);
-            yield return new Country("Nicaragua", "LATIN AMER. & CARIB", 5570129, 129494, 43, 0.7, -1.22, 29.11, 2300, 67.5, 39.7, 24.51, 4.45);
-            yield return new Country("Niger", "SUB-SAHARAN AFRICA", 12525094, 1267000, 9.9, 0, -0.67, 121.69, 800, 17.6, 1.9, 50.73, 20.91);
-            yield return new Country("Nigeria", "SUB-SAHARAN AFRICA", 131859731, 923768, 142.7, 0.09, 0.26, 98.8, 900, 68, 9.3, 40.43, 16.94);
-            yield return new Country("N. Mariana Islands", "OCEANIA", 82459, 477, 172.9, 310.69, 9.61, 7.11, 12500, 97, 254.7, 19.43, 2.29);
-            yield return new Country("Norway", "WESTERN EUROPE", 4610820, 323802, 14.2, 7.77, 1.74, 3.7, 37800, 100, 461.7, 11.46, 9.4);
-            yield return new Country("Oman", "NEAR EAST", 3102229, 212460, 14.6, 0.98, 0.28, 19.51, 13100, 75.8, 85.5, 36.24, 3.81);
-            yield return new Country("Pakistan", "ASIA (EX. NEAR EAST)", 165803560, 803940, 206.2, 0.13, -2.77, 72.44, 2100, 45.7, 31.8, 29.74, 8.23);
-            yield return new Country("Palau", "OCEANIA", 20579, 458, 44.9, 331.66, 2.85, 14.84, 9000, 92, 325.6, 18.03, 6.8);
-            yield return new Country("Panama", "LATIN AMER. & CARIB", 3191319, 78200, 40.8, 3.18, -0.91, 20.47, 6300, 92.6, 137.9, 21.74, 5.36);
-            yield return new Country("Papua New Guinea", "OCEANIA", 5670544, 462840, 12.3, 1.11, 0, 51.45, 2200, 64.6, 10.9, 29.36, 7.25);
-            yield return new Country("Paraguay", "LATIN AMER. & CARIB", 6506464, 406750, 16, 0, -0.08, 25.63, 4700, 94, 49.2, 29.1, 4.49);
-            yield return new Country("Peru", "LATIN AMER. & CARIB", 28302603, 1285220, 22, 0.19, -1.05, 31.94, 5100, 90.9, 79.5, 20.48, 6.23);
-            yield return new Country("Philippines", "ASIA (EX. NEAR EAST)", 89468677, 300000, 298.2, 12.1, -1.5, 23.51, 4600, 92.6, 38.4, 24.89, 5.41);
-            yield return new Country("Poland", "EASTERN EUROPE", 38536869, 312685, 123.3, 0.16, -0.49, 8.51, 11100, 99.8, 306.3, 9.85, 9.89);
-            yield return new Country("Portugal", "WESTERN EUROPE", 10605870, 92391, 114.8, 1.94, 3.57, 5.05, 18000, 93.3, 399.2, 10.72, 10.5);
-            yield return new Country("Puerto Rico", "LATIN AMER. & CARIB", 3927188, 13790, 284.8, 3.63, -1.46, 8.24, 16800, 94.1, 283.1, 12.77, 7.65);
-            yield return new Country("Qatar", "NEAR EAST", 885359, 11437, 77.4, 4.92, 16.29, 18.61, 21500, 82.5, 232, 15.56, 4.72);
-            yield return new Country("Reunion", "SUB-SAHARAN AFRICA", 787584, 2517, 312.9, 8.22, 0, 7.78, 5800, 88.9, 380.9, 18.9, 5.49);
-            yield return new Country("Romania", "EASTERN EUROPE", 22303552, 237500, 93.9, 0.09, -0.13, 26.43, 7000, 98.4, 196.9, 10.7, 11.77);
-            yield return new Country("Russia", "C.W. OF IND. STATES", 142893540, 17075200, 8.4, 0.22, 1.02, 15.39, 8900, 99.6, 280.6, 9.95, 14.65);
-            yield return new Country("Rwanda", "SUB-SAHARAN AFRICA", 8648248, 26338, 328.4, 0, 0, 91.23, 1300, 70.4, 2.7, 40.37, 16.09);
-            yield return new Country("Saint Helena", "SUB-SAHARAN AFRICA", 7502, 413, 18.2, 14.53, 0, 19, 2500, 97, 293.3, 12.13, 6.53);
-            yield return new Country("Saint Kitts & Nevis", "LATIN AMER. & CARIB", 39129, 261, 149.9, 51.72, -7.11, 14.49, 8800, 97, 638.9, 18.02, 8.33);
-            yield return new Country("Saint Lucia", "LATIN AMER. & CARIB", 168458, 616, 273.5, 25.65, -2.67, 13.53, 5400, 67, 303.3, 19.68, 5.08);
-            yield return new Country("St Pierre & Miquelon", "NORTHERN AMERICA", 7026, 242, 29, 49.59, -4.86, 7.54, 6900, 99, 683.2, 13.52, 6.83);
-            yield return new Country("Saint Vincent and the Grenadines", "LATIN AMER. & CARIB", 117848, 389, 303, 21.59, -7.64, 14.78, 2900, 96, 190.9, 16.18, 5.98);
-            yield return new Country("Samoa", "OCEANIA", 176908, 2944, 60.1, 13.69, -11.7, 27.71, 5600, 99.7, 75.2, 16.43, 6.62);
-            yield return new Country("San Marino", "WESTERN EUROPE", 29251, 61, 479.5, 0, 10.98, 5.73, 34600, 96, 704.3, 10.02, 8.17);
-            yield return new Country("Sao Tome & Principe", "SUB-SAHARAN AFRICA", 193413, 1001, 193.2, 20.88, -2.72, 43.11, 1200, 79.3, 36.2, 40.25, 6.47);
-            yield return new Country("Saudi Arabia", "NEAR EAST", 27019731, 1960582, 13.8, 0.13, -2.71, 13.24, 11800, 78.8, 140.6, 29.34, 2.58);
-            yield return new Country("Senegal", "SUB-SAHARAN AFRICA", 11987121, 196190, 61.1, 0.27, 0.2, 55.51, 1600, 40.2, 22.2, 32.78, 9.42);
-            yield return new Country("Serbia", "EASTERN EUROPE", 9396411, 88361, 106.3, 0, -1.33, 12.89, 2200, 93, 285.8,null,null);
-            yield return new Country("Seychelles", "SUB-SAHARAN AFRICA", 81541, 455, 179.2, 107.91, -5.69, 15.53, 7800, 58, 262.4, 16.03, 6.29);
-            yield return new Country("Sierra Leone", "SUB-SAHARAN AFRICA", 6005250, 71740, 83.7, 0.56, 0, 143.64, 500, 31.4, 4, 45.76, 23.03);
-            yield return new Country("Singapore", "ASIA (EX. NEAR EAST)", 4492150, 693, 6482.2, 27.85, 11.53, 2.29, 23700, 92.5, 411.4, 9.34, 4.28);
-            yield return new Country("Slovakia", "EASTERN EUROPE", 5439448, 48845, 111.4, 0, 0.3, 7.41, 13300,null, 220.1, 10.65, 9.45);
-            yield return new Country("Slovenia", "EASTERN EUROPE", 2010347, 20273, 99.2, 0.23, 1.12, 4.45, 19000, 99.7, 406.1, 8.98, 10.31);
-            yield return new Country("Solomon Islands", "OCEANIA", 552438, 28450, 19.4, 18.67, 0, 21.29, 1700,null, 13.4, 30.01, 3.92);
-            yield return new Country("Somalia", "SUB-SAHARAN AFRICA", 8863338, 637657, 13.9, 0.47, 5.37, 116.7, 500, 37.8, 11.3, 45.13, 16.63);
-            yield return new Country("South Africa", "SUB-SAHARAN AFRICA", 44187637, 1219912, 36.2, 0.23, -0.29, 61.81, 10700, 86.4, 107, 18.2, 22);
-            yield return new Country("Spain", "WESTERN EUROPE", 40397842, 504782, 80, 0.98, 0.99, 4.42, 22000, 97.9, 453.5, 10.06, 9.72);
-            yield return new Country("Sri Lanka", "ASIA (EX. NEAR EAST)", 20222240, 65610, 308.2, 2.04, -1.31, 14.35, 3700, 92.3, 61.5, 15.51, 6.52);
-            yield return new Country("Sudan", "SUB-SAHARAN AFRICA", 41236378, 2505810, 16.5, 0.03, -0.02, 62.5, 1900, 61.1, 16.3, 34.53, 8.97);
-            yield return new Country("Suriname", "LATIN AMER. & CARIB", 439117, 163270, 2.7, 0.24, -8.81, 23.57, 4000, 93, 184.7, 18.02, 7.27);
-            yield return new Country("Swaziland", "SUB-SAHARAN AFRICA", 1136334, 17363, 65.5, 0, 0, 69.27, 4900, 81.6, 30.8, 27.41, 29.74);
-            yield return new Country("Sweden", "WESTERN EUROPE", 9016596, 449964, 20, 0.72, 1.67, 2.77, 26800, 99, 715, 10.27, 10.31);
-            yield return new Country("Switzerland", "WESTERN EUROPE", 7523934, 41290, 182.2, 0, 4.05, 4.39, 32700, 99, 680.9, 9.71, 8.49);
-            yield return new Country("Syria", "NEAR EAST", 18881361, 185180, 102, 0.1, 0, 29.53, 3300, 76.9, 153.8, 27.76, 4.81);
-            yield return new Country("Taiwan", "ASIA (EX. NEAR EAST)", 23036087, 35980, 640.3, 4.35, 0, 6.4, 23400, 96.1, 591, 12.56, 6.48);
-            yield return new Country("Tajikistan", "C.W. OF IND. STATES", 7320815, 143100, 51.2, 0, -2.86, 110.76, 1000, 99.4, 33.5, 32.65, 8.25);
-            yield return new Country("Tanzania", "SUB-SAHARAN AFRICA", 37445392, 945087, 39.6, 0.15, -2.06, 98.54, 600, 78.2, 4, 37.71, 16.39);
-            yield return new Country("Thailand", "ASIA (EX. NEAR EAST)", 64631595, 514000, 125.7, 0.63, 0, 20.48, 7400, 92.6, 108.9, 13.87, 7.04);
-            yield return new Country("Togo", "SUB-SAHARAN AFRICA", 5548702, 56785, 97.7, 0.1, 0, 66.61, 1500, 60.9, 10.6, 37.01, 9.83);
-            yield return new Country("Tonga", "OCEANIA", 114689, 748, 153.3, 56.02, 0, 12.62, 2200, 98.5, 97.7, 25.37, 5.28);
-            yield return new Country("Trinidad & Tobago", "LATIN AMER. & CARIB", 1065842, 5128, 207.9, 7.06, -10.83, 24.31, 9500, 98.6, 303.5, 12.9, 10.57);
-            yield return new Country("Tunisia", "NORTHERN AFRICA", 10175014, 163610, 62.2, 0.7, -0.57, 24.77, 6900, 74.2, 123.6, 15.52, 5.13);
-            yield return new Country("Turkey", "NEAR EAST", 70413958, 780580, 90.2, 0.92, 0, 41.04, 6700, 86.5, 269.5, 16.62, 5.97);
-            yield return new Country("Turkmenistan", "C.W. OF IND. STATES", 5042920, 488100, 10.3, 0, -0.86, 73.08, 5800, 98, 74.6, 27.61, 8.6);
-            yield return new Country("Turks & Caicos Is", "LATIN AMER. & CARIB", 21152, 430, 49.2, 90.47, 11.68, 15.67, 9600, 98, 269.5, 21.84, 4.21);
-            yield return new Country("Tuvalu", "OCEANIA", 11810, 26, 454.2, 92.31, 0, 20.03, 1100,null, 59.3, 22.18, 7.11);
-            yield return new Country("Uganda", "SUB-SAHARAN AFRICA", 28195754, 236040, 119.5, 0, 0, 67.83, 1400, 69.9, 3.6, 47.35, 12.24);
-            yield return new Country("Ukraine", "C.W. OF IND. STATES", 46710816, 603700, 77.4, 0.46, -0.39, 20.34, 5400, 99.7, 259.9, 8.82, 14.39);
-            yield return new Country("United Arab Emirates", "NEAR EAST", 2602713, 82880, 31.4, 1.59, 1.03, 14.51, 23200, 77.9, 475.3, 18.96, 4.4);
-            yield return new Country("United Kingdom", "WESTERN EUROPE", 60609153, 244820, 247.6, 5.08, 2.19, 5.16, 27700, 99, 543.5, 10.71, 10.13);
-            yield return new Country("United States", "NORTHERN AMERICA", 298444215, 9631420, 31, 0.21, 3.41, 6.5, 37800, 97, 898, 14.14, 8.26);
-            yield return new Country("Uruguay", "LATIN AMER. & CARIB", 3431932, 176220, 19.5, 0.37, -0.32, 11.95, 12800, 98, 291.4, 13.91, 9.05);
-            yield return new Country("Uzbekistan", "C.W. OF IND. STATES", 27307134, 447400, 61, 0, -1.72, 71.1, 1700, 99.3, 62.9, 26.36, 7.84);
-            yield return new Country("Vanuatu", "OCEANIA", 208869, 12200, 17.1, 20.72, 0, 55.16, 2900, 53, 32.6, 22.72, 7.82);
-            yield return new Country("Venezuela", "LATIN AMER. & CARIB", 25730435, 912050, 28.2, 0.31, -0.04, 22.2, 4800, 93.4, 140.1, 18.71, 4.92);
-            yield return new Country("Vietnam", "ASIA (EX. NEAR EAST)", 84402966, 329560, 256.1, 1.05, -0.45, 25.95, 2500, 90.3, 187.7, 16.86, 6.22);
-            yield return new Country("Virgin Islands", "LATIN AMER. & CARIB", 108605, 1910, 56.9, 9.84, -8.94, 8.03, 17200,null, 652.8, 13.96, 6.43);
-            yield return new Country("Wallis and Futuna", "OCEANIA", 16025, 274, 58.5, 47.08,null,null, 3700, 50, 118.6,null,null);
-            yield return new Country("West Bank", "NEAR EAST", 2460492, 5860, 419.9, 0, 2.98, 19.62, 800,null, 145.2, 31.67, 3.92);
-            yield return new Country("Yemen", "NEAR EAST", 21456188, 527970, 40.6, 0.36, 0, 61.5, 800, 50.2, 37.2, 42.89, 8.3);
-            yield return new Country("Zambia", "SUB-SAHARAN AFRICA", 11502010, 752614, 15.3, 0, 0, 88.29, 800, 80.6, 8.2, 41, 19.93);
-            yield return new Country("Zimbabwe", "SUB-SAHARAN AFRICA", 12236805, 390580, 31.3, 0, 0, 67.69, 1900, 90.7, 26.8, 28.01, 21.84);
-        }
-
-        static IReadOnlyList<Country>? _all;
-
-        public static IReadOnlyList<Country> All
-        {
-            get
-            {
-                if(_all == null)
-                {
-                    _all = GetCountries().ToList().AsReadOnly();
-                }
-
-                return _all;
-            }
-
-        }
-    }
-    
-public class Country
-{
-    public string Name { get; private set; }
-    public string Region { get; private set; }
-    public int Population { get; private set; }
-    //Square Miles
-    public int Area { get; private set; }
-    //Per Square Mile
-    public double PopulationDensity { get; private set; }
-    //Coast / Area
-    public double CoastLine { get; private set; }
-    public double? NetMigration { get; private set; }
-    //per 1000 births
-    public double? InfantMortality { get; private set; }
-    public int GDP { get; private set; }
-    public double? LiteracyPercent { get; private set; }
-    //per 1000
-    public double? Phones { get; private set; }
-    public double? BirthRate { get; private set; }
-    public double? DeathRate { get; private set; }
-
-    public Country(string name, string region, int population, int area, double density, double coast, double? migration, 
-        double? infantMorality, int gdp, double? literacy, double? phones, double? birth, double? death)
-    {
-        Name = name;
-        Region = region;
-        Population = population;
-        Area = area;
-        PopulationDensity = density;
-        CoastLine = coast;
-        NetMigration = migration;
-        InfantMortality = infantMorality;
-        GDP = gdp;
-        LiteracyPercent = literacy;
-        BirthRate = birth;
-        DeathRate = death;
+        DataContext = new DataGridDemoViewModel();
     }
 }
\ No newline at end of file
diff --git a/demo/Semi.Avalonia.Demo/ViewModels/DataGridDemoViewModel.cs b/demo/Semi.Avalonia.Demo/ViewModels/DataGridDemoViewModel.cs
new file mode 100644
index 0000000..a459d39
--- /dev/null
+++ b/demo/Semi.Avalonia.Demo/ViewModels/DataGridDemoViewModel.cs
@@ -0,0 +1,153 @@
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Linq;
+using Avalonia.Collections;
+using CommunityToolkit.Mvvm.ComponentModel;
+
+namespace Semi.Avalonia.Demo.ViewModels;
+
+public class DataGridDemoViewModel: ObservableObject
+{
+    public ObservableCollection<Song> GridData1 { get; set; }
+    
+    public DataGridCollectionView GridData2 { get; set; }
+    
+    public ObservableCollection<SongViewModel> GridData3 { get; set; }
+
+    public DataGridDemoViewModel()
+    {
+        GridData1 = new ObservableCollection<Song>(Song.Songs);
+        GridData2 = new DataGridCollectionView(Song.Songs);
+        GridData2.GroupDescriptions.Add(new DataGridPathGroupDescription("Album"));
+        GridData3 = new ObservableCollection<SongViewModel>(Song.Songs.Take(10).Select(a=>new SongViewModel()
+        {
+            Title = a.Title,
+            Artist = a.Artist,
+            Album = a.Album,
+            CountOfComment = a.CountOfComment,
+            IsSelected = false
+        }));
+    }
+}
+
+public class Song
+{
+    public string? Title { get; set; }
+    public string? Artist { get; set; }
+    public TimeSpan? Duration { get; set; }
+    public string? Album { get; set; }
+    public int CountOfComment { get; set; }
+    public string Url { get; set; }
+
+    public Song(string title, string artist, int m, int s, string album, int countOfComment, int netEaseId)
+    {
+        Title = title;
+        Artist = artist;
+        Duration = new TimeSpan(0, m, s);
+        Album = album;
+        CountOfComment = countOfComment;
+        Url = $"https://music.163.com/song?id={netEaseId}";
+        
+    }
+
+    public static List<Song> Songs { get; set; } = new List<Song>()
+    {
+        new("好肚有肚(feat.李玲玉)", "熊猫堂ProducePandas", 2, 50, "A.S.I.A", 730, 1487039339),
+        new("荒诞秀", "熊猫堂ProducePandas", 3, 15, "A.S.I.A", 639, 1487037601),
+        new("长大", "熊猫堂ProducePandas", 4, 6, "A.S.I.A", 1114, 1487037690),
+        new("招财猫(feat.纪粹希(G-Tracy))", "熊猫堂ProducePandas", 3, 37, "A.S.I.A", 361, 1487039632),
+        new("千转", "熊猫堂ProducePandas", 4, 0, "A.S.I.A", 1115, 1477312398),
+        new("辣辣辣", "熊猫堂ProducePandas", 3, 24, "A.S.I.A", 1873, 1465043716),
+        new("碎碎念", "熊猫堂ProducePandas", 3, 25, "A.S.I.A", 676, 1474142064),
+        new("盘他", "熊猫堂ProducePandas", 2, 16, "A.S.I.A", 365, 1481652786),
+        new("Na Na Na", "熊猫堂ProducePandas", 3, 26, "A.S.I.A", 312, 1469022662),
+        new("Indigo", "熊猫堂ProducePandas", 3, 15, "A.S.I.A", 137, 1487039517),
+        new("饕餮人间", "熊猫堂ProducePandas", 3, 20, "饕餮人间", 1295, 1499584605),
+        new("七步咙咚呛", "熊猫堂ProducePandas", 3, 10, "七步咙咚呛", 175, 1809095152),
+        new("大惊小怪", "熊猫堂ProducePandas", 3, 32, "大惊小怪", 10420, 1847477425),
+        new("工具人", "熊猫堂ProducePandas", 2, 46, "大惊小怪", 1135, 1847476499),
+        new("以梦为马", "熊猫堂ProducePandas", 4, 19, "大惊小怪", 18361, 1836034373),
+        new("以梦为马(Piano Version)", "熊猫堂ProducePandas", 3, 4, "大惊小怪", 570, 1847477423),
+        new("The ONE", "熊猫堂ProducePandas", 2, 58, "The ONE", 1508, 1864329424),
+        new("The ONE(日文版)", "熊猫堂ProducePandas", 2, 57, "The ONE", 385, 1864329429),
+        new("以梦为马 (壮志骄阳版)", "熊猫堂ProducePandas", 4, 19, "以梦为马 (壮志骄阳版)", 161, 1865138896),
+        new("New Horse", "熊猫堂ProducePandas", 2, 30, "emo了", 643, 1887021307),
+        new("不例外", "熊猫堂ProducePandas", 3, 31, "emo了", 1818, 1887022665),
+        new("满意", "熊猫堂ProducePandas", 4, 32, "emo了", 1081, 1882433472),
+        new("就算与全世界为敌也要跟你在一起", "熊猫堂ProducePandas", 3, 32, "emo了", 2119, 1881759960),
+        new("The ONE", "熊猫堂ProducePandas", 2, 58, "emo了", 67, 1887022648),
+        new("口香糖", "熊猫堂ProducePandas", 3, 10, "emo了", 2181, 1885502254),
+        new("Suuuuuuper Mario", "熊猫堂ProducePandas", 3, 32, "emo了", 1010, 1887021318),
+        new("饕餮人间", "熊猫堂ProducePandas", 3, 22, "emo了", 109, 1887021320),
+        new("以梦为马 (壮志骄阳版)", "熊猫堂ProducePandas", 4, 21, "emo了", 34, 1887022666),
+        new("The ONE(日文版)", "熊猫堂ProducePandas", 2, 57, "emo了", 27, 1887022646),
+        new("满意(DJheap九天版)", "熊猫堂ProducePandas", 4, 31, "emo了", 31, 1901605941),
+        new("一眼万年", "熊猫堂ProducePandas", 3, 54, "一眼万年", 20, 1922599361),
+        new("冲刺", "熊猫堂ProducePandas", 3, 49, "冲刺吧", 1006, 1932878194),
+        new("滴答滴", "熊猫堂ProducePandas", 2, 30, "爱的赏味期限", 86, 1957515790),
+        new("热带季风", "熊猫堂ProducePandas", 2, 45, "爱的赏味期限", 212, 1957514964),
+        new("渣", "熊猫堂ProducePandas", 3, 28, "爱的赏味期限", 22, 1957514965),
+        new("独特", "熊猫堂ProducePandas", 3, 33, "爱的赏味期限", 62, 1957514966),
+        new("雨后", "熊猫堂ProducePandas", 4, 15, "爱的赏味期限", 23, 1957514967),
+        new("然后然后", "熊猫堂ProducePandas", 3, 50, "爱的赏味期限", 108, 1957514968),
+        new("丢", "熊猫堂ProducePandas", 3, 26, "爱的赏味期限", 30, 1957515792),
+        new("热带疾风(FACEVOID桃心连哥 Remix)", "熊猫堂ProducePandas", 3, 23, "爱的赏味期限", 55, 1957515793),
+        new("COSMIC ANTHEM -Japanese Ver.-", "熊猫堂ProducePandas", 3, 11, "COSMIC ANTHEM / 手紙", 0, 1977171493),
+        new("手紙 (「長大-You Raise Me Up-」-Japanese Ver.-)", "熊猫堂ProducePandas", 4, 11, "COSMIC ANTHEM / 手紙", 0,
+            1977171494),
+        new("COSMIC ANTHEM -Chinese Ver.-", "熊猫堂ProducePandas", 3, 31, "COSMIC ANTHEM / 手紙", 0, 1977172202),
+        new("世界晚安", "熊猫堂ProducePandas", 2, 59, "世界晚安", 652, 1985063377),
+        new("世界晚安(泰文版)", "熊猫堂ProducePandas", 2, 59, "世界晚安", 134, 1987842504),
+        new("世界晚安(钢琴版)", "熊猫堂ProducePandas", 3, 2, "世界晚安", 76, 1990475933),
+        new("世界晚安(泰文钢琴版)", "熊猫堂ProducePandas", 3, 2, "世界晚安", 29, 1990475934),
+        new("世界晚安(DJ沈念版)", "熊猫堂ProducePandas", 3, 9, "世界晚安", 34, 2014263184),
+        new("世界晚安(钢琴配乐)", "熊猫堂ProducePandas", 2, 59, "世界晚安", 11, 2014263185),
+        new("明年也要好好长大", "熊猫堂ProducePandas", 3, 12, "明年也要好好长大", 0, 2010515162),
+        new("320万年前（DJ沈念版）", "熊猫堂ProducePandas", 3, 21, "320万年前", 8, 2055888636),
+        new("320万年前", "熊猫堂ProducePandas", 3, 7, "W.O.R.L.D.", 329, 2049770469),
+        new("隐德来希", "熊猫堂ProducePandas", 3, 3, "W.O.R.L.D.", 594, 2061317924),
+        new("孔明", "熊猫堂ProducePandas", 3, 59, "W.O.R.L.D.", 91, 2063175274),
+        new("锦鲤卟噜噜", "熊猫堂ProducePandas", 3, 5, "W.O.R.L.D.", 67, 2059208262),
+        new("指鹿为马", "熊猫堂ProducePandas", 3, 12, "W.O.R.L.D.", 74, 2063175272),
+        new("热带季风Remix", "熊猫堂ProducePandas", 3, 22, "W.O.R.L.D.", 23, 2063173319),
+        new("加州梦境", "熊猫堂ProducePandas", 2, 56, "W.O.R.L.D.", 1662, 2063173324),
+        new("渐进自由", "熊猫堂ProducePandas", 4, 19, "W.O.R.L.D.", 124, 2063173321),
+        new("世界所有的烂漫", "熊猫堂ProducePandas", 3, 30, "W.O.R.L.D.", 335, 2053388775),
+    };
+}
+
+public class SongViewModel: ObservableObject
+{
+    private string? _title;
+    private string? _artist;
+    private string? _album;
+    private int _countOfComment;
+    private bool? _isSelected;
+    public string? Title
+    {
+        get => _title;
+        set => SetProperty(ref _title, value);
+    }
+    public string? Artist
+    {
+        get => _artist;
+        set => SetProperty(ref _artist, value);
+    }
+    public string? Album
+    {
+        get => _album;
+        set => SetProperty(ref _album, value);
+    }
+    public int CountOfComment
+    {
+        get => _countOfComment;
+        set => SetProperty(ref _countOfComment, value);
+    }
+    public bool? IsSelected
+    {
+        get => _isSelected;
+        set => SetProperty(ref _isSelected, value);
+    }
+    
+}
\ No newline at end of file