RichTextBox.AllowDrop RichTextBox.AllowDrop RichTextBox.AllowDrop RichTextBox.AllowDrop Property

定义

获取或设置一个值,该值指示控件是否允许拖放操作。Gets or sets a value indicating whether the control will enable drag-and-drop operations.

public:
 virtual property bool AllowDrop { bool get(); void set(bool value); };
[System.ComponentModel.Browsable(false)]
public override bool AllowDrop { get; set; }
member this.AllowDrop : bool with get, set
Public Overrides Property AllowDrop As Boolean

属性值

如果控件中允许拖放操作,则为 true;否则为 falsetrue if drag-and-drop is enabled in the control; otherwise, false.

示例

下面的代码示例演示如何使用ListBox包含要放置RichTextBox到控件中的项的控件执行拖放操作。The following code example demonstrates how to perform drag-and-drop operations using a ListBox control that contains items to drop into a RichTextBox control. 窗体的构造函数将AllowDrop属性设置为true ,以便在中执行拖放RichTextBox操作。The constructor of the form sets the AllowDrop property to true to enable drag-and-drop operations to occur in the RichTextBox. 该示例通过调用MouseDown DoDragDrop方法,使用ListBox的事件来启动拖动操作。The example uses the MouseDown event of the ListBox to start the drag operation by calling the DoDragDrop method. 该示例使用DragEnter事件确定要拖动到的RichTextBox项是否为有效的数据类型。The example uses the DragEnter event to determine if an item being dragged into the RichTextBox is a valid data type. DragDrop事件执行拖动的项到实际放RichTextBox控件中的当前光标位置在RichTextBoxThe DragDrop event performs the actual dropping of a dragged item into the RichTextBox control at the current cursor location within the RichTextBox. 此示例要求DragDropDragEnter事件已连接到示例中定义的事件处理程序。This example requires that the DragDrop and DragEnter events have been connected to the event handlers defined in the example.

public:
   Form1()
   {
      InitializeComponent();
      
      // Sets the control to allow drops, and then adds the necessary event handlers.
      this->richTextBox1->AllowDrop = true;
   }

private:
   void listBox1_MouseDown( Object^ sender, System::Windows::Forms::MouseEventArgs^ e )
   {
      // Determines which item was selected.
      ListBox^ lb = (dynamic_cast<ListBox^>(sender));
      Point pt = Point(e->X,e->Y);

      //Retrieve the item at the specified location within the ListBox.
      int index = lb->IndexFromPoint( pt );

      // Starts a drag-and-drop operation.
      if ( index >= 0 )
      {
         // Retrieve the selected item text to drag into the RichTextBox.
         lb->DoDragDrop( lb->Items[ index ]->ToString(), DragDropEffects::Copy );
      }
   }

   void richTextBox1_DragEnter( Object^ /*sender*/, DragEventArgs^ e )
   {
      // If the data is text, copy the data to the RichTextBox control.
      if ( e->Data->GetDataPresent( "Text" ) )
            e->Effect = DragDropEffects::Copy;
   }

   void richTextBox1_DragDrop( Object^ /*sender*/, DragEventArgs^ e )
   {
      // Paste the text into the RichTextBox where at selection location.
      richTextBox1->SelectedText = e->Data->GetData( "System.String", true )->ToString();
   }
public Form1()
{
   InitializeComponent();
   // Sets the control to allow drops, and then adds the necessary event handlers.
   this.richTextBox1.AllowDrop = true;
}
 
private void listBox1_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e)
{
   // Determines which item was selected.
   ListBox lb =( (ListBox)sender);
   Point pt = new Point(e.X,e.Y);
   //Retrieve the item at the specified location within the ListBox.
   int index = lb.IndexFromPoint(pt);

   // Starts a drag-and-drop operation.
   if(index>=0) 
   {
      // Retrieve the selected item text to drag into the RichTextBox.
      lb.DoDragDrop(lb.Items[index].ToString(), DragDropEffects.Copy);
   }
}

private void richTextBox1_DragEnter(object sender, DragEventArgs e)
{
   // If the data is text, copy the data to the RichTextBox control.
   if(e.Data.GetDataPresent("Text"))
      e.Effect = DragDropEffects.Copy;
}

private void richTextBox1_DragDrop(object sender, DragEventArgs e) 
{
   // Paste the text into the RichTextBox where at selection location.
   richTextBox1.SelectedText =  e.Data.GetData("System.String", true).ToString();
}

Public Sub New()
   MyBase.New()

   'This call is required by the Windows Form Designer.
   InitializeComponent()

   richTextBox1.AllowDrop = True

End Sub

Private Sub listBox1_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles listBox1.MouseDown
   ' Determines which item was selected.
   Dim lb As ListBox = CType(sender, ListBox)
   Dim pt As New Point(e.X, e.Y)
   'Retrieve the item at the specified location within the ListBox.
   Dim index As Integer = lb.IndexFromPoint(pt)

   ' Starts a drag-and-drop operation.
   If index >= 0 Then
      ' Retrieve the selected item text to drag into the RichTextBox.
      lb.DoDragDrop(lb.Items(index).ToString(), DragDropEffects.Copy)
   End If
End Sub


Private Sub richTextBox1_DragEnter(ByVal sender As Object, ByVal e As DragEventArgs) Handles richTextBox1.DragEnter
   ' If the data is text, copy the data to the RichTextBox control.
   If e.Data.GetDataPresent("Text") Then
      e.Effect = DragDropEffects.Copy
   End If
End Sub

Private Sub richTextBox1_DragDrop(ByVal sender As Object, ByVal e As DragEventArgs) Handles richTextBox1.DragDrop
   ' Paste the text into the RichTextBox where at selection location.
   richTextBox1.SelectedText = e.Data.GetData("System.String", True).ToString()
End Sub

适用于