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ItemDragDrop Event

Summary

Occurs when data is being dragged or dropped from/to this ImageViewer.

Syntax
C#
VB
C++
public event EventHandler<ImageViewerItemDragDropEventArgs> ItemDragDrop 
Public Event ItemDragDrop As EventHandler(Of Leadtools.Controls.ImageViewerItemDragDropEventArgs) 
public:  
   event EventHandler<Leadtools::Controls::ImageViewerItemDragDropEventArgs^>^ ItemDragDrop 

Remarks

For more information refer to Image Viewer Drag and Drop.

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:

C#
VB
using Leadtools; 
using Leadtools.Controls; 
using Leadtools.Codecs; 
using Leadtools.Drawing; 
using LeadtoolsExamples.Common; 
using Leadtools.ImageProcessing; 
using Leadtools.ImageProcessing.Color; 
 
public void ImageViewerItemDragDrop_Example() 
{ 
   _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; 
 
} 
Imports Leadtools 
Imports Leadtools.Controls 
Imports Leadtools.Codecs 
Imports Leadtools.Drawing 
Imports Leadtools.ImageProcessing 
Imports Leadtools.ImageProcessing.Color 
Imports LeadtoolsControlsExamples.LeadtoolsExamples.Common 
 
Public Sub ImageViewerItemDragDrop_Example() 
 
   _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 
End Sub 

Event Data

ParameterTypeDescription
senderobjectThe source of the event.
eImageViewerItemDragDropEventArgsThe event data.

Requirements

Target Platforms

Help Version 20.0.2019.3.11
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Leadtools.Controls Assembly