How can I implement drag-and-drop from other controls onto the Diagram?

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How can I implement drag-and-drop from other controls onto the Diagram?

The sample included in this KnowledgeBase demonstrates how you can implement drag and drop support in an Essential Diagram application.

An image from a Windows Forms PictureBox control can be dragged and dropped onto the Diagram. A node of type BitmapNode is created.
A node from an Essential Tools' TreeViewAdv control can be dragged and dropped onto the Diagram. A node of type TextNode is created.
Note:
This sample uses the TreeViewAdv control from Essential tools.

private void diagram1_DragEnter(object sender, System.Windows.Forms.DragEventArgs e)
  {
   //Allow Drop Cursor only if it is a Diagram Node or a Bitmap
   if ( (e.Data.GetDataPresent(typeof(NodeCollection))) | (e.Data.GetDataPresent(DataFormats.Bitmap))|(e.Data.GetDataPresent(typeof(TreeNodeAdv))))
   {
    e.Effect = DragDropEffects.All;
   }
   else
    e.Effect = DragDropEffects.None;
  }
   private void diagram1_DragDrop(object sender, System.Windows.Forms.DragEventArgs e)
  {
   Point pt = this.diagram1.PointToClient(new Point(e.X, e.Y));
   //if this is a bitmap then insert a BitmapNode in Diagram
   if (e.Data.GetDataPresent(DataFormats.Bitmap))
   {
    BitmapNode bmpnode = new BitmapNode((Bitmap)e.Data.GetData(DataFormats.Bitmap));
    InsertNodesCmd insCmd = new InsertNodesCmd( this.diagram1.Model, bmpnode, this.diagram1.View.DeviceToView( pt ) );
diagram1.Controller.ExecuteCommand(insCmd);
   }
   else if(e.Data.GetDataPresent(typeof(TreeNodeAdv)))
   {
    TreeNodeAdv treenode = (TreeNodeAdv) e.Data.GetData(typeof(TreeNodeAdv));
    TextNode textnode = new TextNode();
    textnode.Text = treenode.Text;
    textnode.SizeToText(new SizeF(0,0));
    textnode.Location = this.diagram1.View.DeviceToView( pt );
this.diagram1.Model.AppendChild(textnode);
    this.diagram1.Refresh();
   }
  }

Private Sub diagram1_DragEnter(ByVal sender As Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles diagram1.DragEnter
'Allow Drop Cursor only if it is a Diagram Node or a Bitmap
If e.Data.GetDataPresent(GetType(NodeCollection)) Or e.Data.GetDataPresent(DataFormats.Bitmap) Or e.Data.GetDataPresent(GetType(TreeNodeAdv)) Then
e.Effect = DragDropEffects.All
Else
e.Effect = DragDropEffects.None
End If
End Sub 'diagram1_DragEnter
Private Sub diagram1_DragDrop(ByVal sender As Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles diagram1.DragDrop
Dim pt As Point = Me.diagram1.PointToClient(New Point(e.X, e.Y))
'if this is a bitmap then insert a BitmapNode in Diagram
If e.Data.GetDataPresent(DataFormats.Bitmap) Then
Dim bmpnode As BitmapNode = New BitmapNode(CType(e.Data.GetData(DataFormats.Bitmap), Bitmap))
Dim insCmd As InsertNodesCmd = New InsertNodesCmd(Me.diagram1.Model, bmpnode, Me.diagram1.View.DeviceToView(pt))
diagram1.Controller.ExecuteCommand(insCmd)
ElseIf e.Data.GetDataPresent(GetType(TreeNodeAdv)) Then
Dim treenode As TreeNodeAdv = CType(e.Data.GetData(GetType(TreeNodeAdv)), TreeNodeAdv)
Dim textnode As TextNode = New TextNode
textnode.Text = treenode.Text
textnode.SizeToText(New SizeF(0, 0))
textnode.Location = Me.diagram1.View.DeviceToView(pt)
Me.diagram1.Model.AppendChild(textnode)
Me.diagram1.Refresh()
End If
End Sub 'diagram1_DragDrop

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