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ListBox.IndexFromPoint Method

Returns the zero-based index of the item at the specified coordinates.

Overload List

Returns the zero-based index of the item at the specified coordinates.

[Visual Basic] Overloads Public Function IndexFromPoint(Point) As Integer
[C#] public int IndexFromPoint(Point);
[C++] public: int IndexFromPoint(Point);
[JScript] public function IndexFromPoint(Point) : int;

Returns the zero-based index of the item at the specified coordinates.

[Visual Basic] Overloads Public Function IndexFromPoint(Integer, Integer) As Integer
[C#] public int IndexFromPoint(int, int);
[C++] public: int IndexFromPoint(int, int);
[JScript] public function IndexFromPoint(int, int) : int;

Example

[Visual Basic, C#, C++] The following example demonstrates how to perform drag and drop operations using a ListBox control that contains items to drop into a RichTextBox control. The constructor of the form sets the AllowDrop property to true to enable drag and drop to occur in the RichTextBox. The example uses the MouseDown event of the ListBox to start the drag operation by calling the DoDragDrop method. The example uses the DragEnter event to determine if an item being dragged into the RichTextBox is a valid data type. The DragDrop event performs the actual dropping of a dragged item into the RichTextBox control at the current cursor location within the RichTextBox. This example assumes that the DragDrop and DragEnter events have been connected to the event handlers defined in the example.

[Visual Basic, C#, C++] Note   This example shows how to use one of the overloaded versions of IndexFromPoint. For other examples that might be available, see the individual overload topics.
[Visual Basic] 
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 'listBox1_MouseDown


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 'richTextBox1_DragEnter

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 'richTextBox1_DragDrop


[C#] 
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();
}


[C++] 
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->Item[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(S"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(S"System.String", true)->ToString();
   }

[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button Language Filter in the upper-left corner of the page.

See Also

ListBox Class | ListBox Members | System.Windows.Forms Namespace

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