* 日期、时间选择框增加CanEmpty，输入可为空

SunnyUI.Demo/Controls/FCombobox.Designer.cs

@@ -127,6 +127,7 @@
             // 
             // uiDatetimePicker1
             // 
+            this.uiDatetimePicker1.CanEmpty = true;
             this.uiDatetimePicker1.FillColor = System.Drawing.Color.White;
             this.uiDatetimePicker1.Font = new System.Drawing.Font("微软雅黑", 12F);
             this.uiDatetimePicker1.Location = new System.Drawing.Point(388, 136);
@@ -184,6 +185,7 @@
             // 
             // uiTimePicker1
             // 
+            this.uiTimePicker1.CanEmpty = true;
             this.uiTimePicker1.FillColor = System.Drawing.Color.White;
             this.uiTimePicker1.Font = new System.Drawing.Font("微软雅黑", 12F);
             this.uiTimePicker1.Location = new System.Drawing.Point(188, 136);
@@ -225,6 +227,7 @@
             // 
             // uiDatePicker1
             // 
+            this.uiDatePicker1.CanEmpty = true;
             this.uiDatePicker1.FillColor = System.Drawing.Color.White;
             this.uiDatePicker1.Font = new System.Drawing.Font("微软雅黑", 12F);
             this.uiDatePicker1.Location = new System.Drawing.Point(30, 136);

SunnyUI/Controls/UIComboBox.cs

@@ -83,6 +83,7 @@ namespace Sunny.UI
         protected override void ItemForm_ValueChanged(object sender, object value)
         {
             SelectedIndex = ListBox.SelectedIndex;
+            Box_SelectedIndexChanged(null, null);
             Invalidate();
         }
 

SunnyUI/Controls/UIDatePicker.cs

@@ -41,6 +41,10 @@ namespace Sunny.UI
             TextChanged += UIDatePicker_TextChanged;
         }
 
+        [DefaultValue(false)]
+        [Description("日期输入时，是否可空显示"), Category("SunnyUI")]
+        public bool CanEmpty { get; set; }
+
         private void UIDatePicker_TextChanged(object sender, EventArgs e)
         {
             if (Text.Length == MaxLength)
@@ -59,6 +63,11 @@ namespace Sunny.UI
 
         private void UIDatePicker_LostFocus(object sender, EventArgs e)
         {
+            if (Text.IsNullOrEmpty())
+            {
+                if (CanEmpty) return;
+            }
+
             try
             {
                 DateTime dt = Text.ToDateTime(DateFormat);

SunnyUI/Controls/UIDateTimePicker.cs

@@ -48,6 +48,10 @@ namespace Sunny.UI
 
         }
 
+        [DefaultValue(false)]
+        [Description("日期输入时，是否可空显示"), Category("SunnyUI")]
+        public bool CanEmpty { get; set; }
+
         public UIDatetimePicker()
         {
             InitializeComponent();
@@ -77,6 +81,11 @@ namespace Sunny.UI
 
         private void UIDatePicker_LostFocus(object sender, EventArgs e)
         {
+            if (Text.IsNullOrEmpty())
+            {
+                if (CanEmpty) return;
+            }
+
             try
             {
                 DateTime dt = Text.ToDateTime(DateFormat);

SunnyUI/Controls/UITimePicker.cs

@@ -56,6 +56,10 @@ namespace Sunny.UI
             MaxLength = 8;
         }
 
+        [DefaultValue(false)]
+        [Description("日期输入时，是否可空显示"), Category("SunnyUI")]
+        public bool CanEmpty { get; set; }
+
         private void UIDatePicker_TextChanged(object sender, EventArgs e)
         {
             if (Text.Length == MaxLength)
@@ -74,6 +78,11 @@ namespace Sunny.UI
 
         private void UIDatePicker_LostFocus(object sender, EventArgs e)
         {
+            if (Text.IsNullOrEmpty())
+            {
+                if (CanEmpty) return;
+            }
+
             try
             {
                 DateTime dt = (DateTime.Now.DateString() + " " + Text).ToDateTime(DateTimeEx.DateFormat + " " + timeFormat);