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(Leadtools.Controls)
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ItemDragDrop Event




Leadtools.Controls Assembly > Leadtools.Controls Namespace > ImageViewer Class : ItemDragDrop Event
Occurs when data is being dragged or dropped from/to this ImageViewer.
Syntax
Event Data

The event handler receives an argument of type ImageViewerItemDragDropEventArgs containing data related to this event. The following ImageViewerItemDragDropEventArgs properties provide information specific to this event.

PropertyDescription
Abort Gets or a sets a value that indicate whether drag/drop operation is to be aborted.
Effect Current drop effect.
Format Format of the drop object.
Location Location of the drag item.
NativeEvent Native event that initiated this drag/drop operation
Operation Current drag operation.
SourceImageViewer Image Viewer that initiated the drag event.
SourceItem The item that originated this drag/drop operation.
TargetImageViewer Current target image viewer for this drop operation.
TargetItem The target item for this drop operation.
Remarks

For more information refer to Image Viewer Drag and Drop.

ImageViewerItemDragDropEventArgs
Example

For an example on using the image viewer as the source of a drag/drop operation, refer to ImageViewerDragInteractiveMode.

This example will show how to use the ImageViewer as the drop target of a drag/drop operation.

Start with the ImageViewer example, remove all the code inside the example function (search for the "// TODO: add example code here" comment) and insert the following code:

Copy Code   
Imports Leadtools
Imports Leadtools.Controls
Imports Leadtools.Codecs
Imports Leadtools.Drawing
Imports Leadtools.ImageProcessing
Imports Leadtools.ImageProcessing.Color

_imageViewer.AllowDrop = True
_imageViewer.BringToFront()
_imageViewer.ActiveItem = _imageViewer.Items(0)

Dim dragMode As New ImageViewerDragInteractiveMode()
dragMode.AllowedEffects = DragDropEffects.Copy Or DragDropEffects.Move Or DragDropEffects.Link

_imageViewer.InteractiveModes.BeginUpdate()
dragMode = New ImageViewerDragInteractiveMode()
dragMode.AllowedEffects = DragDropEffects.Copy Or DragDropEffects.Move Or DragDropEffects.Link
_imageViewer.InteractiveModes.Add(dragMode)
_imageViewer.InteractiveModes.EndUpdate()

Dim handler As EventHandler(Of ImageViewerItemDragDropEventArgs) =
Sub(sender, e)
   Select Case e.Operation
      Case ImageViewerItemDragDropOperation.DragEnter
         Console.WriteLine(String.Format("DragDrop Operation:{0} {1} {2}", e.Operation, e.Effect, e.Format))
         If Not e.SourceImageViewer Is Nothing Then
            If Not e.TargetImageViewer Is Nothing Then
               Console.WriteLine(String.Format("  SrcViewer:{0} DstViewer:{1}", e.SourceImageViewer.Name, e.TargetImageViewer.Name))
            Else
               Console.WriteLine(String.Format("  SrcViewer:{0} DstViewer:{1}", e.SourceImageViewer.Name, "null"))
            End If
         Else
            If Not e.TargetImageViewer Is Nothing Then
               Console.WriteLine(String.Format("  SrcViewer:{0} DstViewer:{1}", "null", e.TargetImageViewer.Name))
            Else
               Console.WriteLine(String.Format("  SrcViewer:{0} DstViewer:{1}", "null", "null"))
            End If
         End If
         If Not e.SourceItem Is Nothing Then
            If Not e.TargetItem Is Nothing Then
               Console.WriteLine(String.Format("  SrcItem:{0} DstItem:{1}", e.SourceImageViewer.Items.IndexOf(e.SourceItem).ToString(), _
                                               e.TargetImageViewer.Items.IndexOf(e.TargetItem).ToString()))
            Else
               Console.WriteLine(String.Format("  SrcItem:{0} DstItem:{1}", e.SourceImageViewer.Items.IndexOf(e.SourceItem).ToString(), "null"))
            End If
         Else
            If Not e.TargetItem Is Nothing Then
               Console.WriteLine(String.Format("  SrcItem:{0} DstItem:{1}", "null", e.TargetImageViewer.Items.IndexOf(e.TargetItem).ToString()))
            Else
               Console.WriteLine(String.Format("  SrcItem:{0} DstItem:{1}", "null", "null"))
            End If
         End If

      Case ImageViewerItemDragDropOperation.DragOver
         Console.WriteLine(String.Format("DragDrop Operation:{0} {1} {2}", e.Operation, e.Effect, e.Format))
         If Not e.SourceImageViewer Is Nothing Then
            If Not e.TargetImageViewer Is Nothing Then
               Console.WriteLine(String.Format("  SrcViewer:{0} DstViewer:{1}", e.SourceImageViewer.Name, e.TargetImageViewer.Name))
            Else
               Console.WriteLine(String.Format("  SrcViewer:{0} DstViewer:{1}", e.SourceImageViewer.Name, "null"))
            End If
         Else
            If Not e.TargetImageViewer Is Nothing Then
               Console.WriteLine(String.Format("  SrcViewer:{0} DstViewer:{1}", "null", e.TargetImageViewer.Name))
            Else
               Console.WriteLine(String.Format("  SrcViewer:{0} DstViewer:{1}", "null", "null"))
            End If
         End If
         If Not e.SourceItem Is Nothing Then
            If Not e.TargetItem Is Nothing Then
               Console.WriteLine(String.Format("  SrcItem:{0} DstItem:{1}", e.SourceImageViewer.Items.IndexOf(e.SourceItem).ToString(), _
                                               e.TargetImageViewer.Items.IndexOf(e.TargetItem).ToString()))
            Else
               Console.WriteLine(String.Format("  SrcItem:{0} DstItem:{1}", e.SourceImageViewer.Items.IndexOf(e.SourceItem).ToString(), "null"))
            End If
         Else
            If Not e.TargetItem Is Nothing Then
               Console.WriteLine(String.Format("  SrcItem:{0} DstItem:{1}", "null", e.TargetImageViewer.Items.IndexOf(e.TargetItem).ToString()))
            Else
               Console.WriteLine(String.Format("  SrcItem:{0} DstItem:{1}", "null", "null"))
            End If
         End If

      Case Else
   End Select
End Sub

AddHandler _imageViewer.ItemDragDrop, handler
using Leadtools;
using Leadtools.Controls;
using Leadtools.Codecs;
using Leadtools.Drawing;
using Leadtools.ImageProcessing;
using Leadtools.ImageProcessing.Color;

_imageViewer.AllowDrop = true;
_imageViewer.BringToFront();
_imageViewer.ActiveItem = _imageViewer.Items[0];

var dragMode = new ImageViewerDragInteractiveMode();
dragMode.AllowedEffects = DragDropEffects.Copy | DragDropEffects.Move | DragDropEffects.Link;

_imageViewer.InteractiveModes.BeginUpdate();
dragMode = new ImageViewerDragInteractiveMode();
dragMode.AllowedEffects = DragDropEffects.Copy | DragDropEffects.Move | DragDropEffects.Link;
_imageViewer.InteractiveModes.Add(dragMode);
_imageViewer.InteractiveModes.EndUpdate();

EventHandler<ImageViewerItemDragDropEventArgs> handler = (sender, e) =>
{
   switch (e.Operation)
   {
      case ImageViewerItemDragDropOperation.DragEnter:
         {
            Console.WriteLine(string.Format("DragDrop Operation:{0} {1} {2}", e.Operation, e.Effect, e.Format));
            Console.WriteLine(string.Format("  SrcViewer:{0} DstViewer:{1}",
               e.SourceImageViewer != null ? e.SourceImageViewer.Name : "null",
               e.TargetImageViewer != null ? e.TargetImageViewer.Name : "null"));
            Console.WriteLine(string.Format("  SrcItem:{0} DstItem:{1}",
               e.SourceItem != null ? e.SourceImageViewer.Items.IndexOf(e.SourceItem).ToString() : "null",
               e.TargetItem != null ? e.TargetImageViewer.Items.IndexOf(e.TargetItem).ToString() : "null"));
         }
         break;

      case ImageViewerItemDragDropOperation.DragOver:
         {
            Console.WriteLine(string.Format("DragDrop Operation:{0} {1} {2}", e.Operation, e.Effect, e.Format));
            Console.WriteLine(string.Format("  SrcViewer:{0} DstViewer:{1}",
               e.SourceImageViewer != null ? e.SourceImageViewer.Name : "null",
               e.TargetImageViewer != null ? e.TargetImageViewer.Name : "null"));
            Console.WriteLine(string.Format("  SrcItem:{0} DstItem:{1}",
               e.SourceItem != null ? e.SourceImageViewer.Items.IndexOf(e.SourceItem).ToString() : "null",
               e.TargetItem != null ? e.TargetImageViewer.Items.IndexOf(e.TargetItem).ToString() : "null"));
         }
         break;

      default:
         break;
   }
};

_imageViewer.ItemDragDrop += handler;
Requirements

Target Platforms

See Also

Reference

ImageViewer Class
ImageViewer Members

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