Hi,

Does drag-and-drop work fine, but the icon is not changed correctly? or drag-and-drop does not work at all?

Stoyan

Hello Eugen,

Have you set FlowChart.AllowDrop = true?

I have modified the Flowcharter example as follows:

private void NodeList_OnMouseDown(object sender, System.Windows.Forms.MouseEventArgs e)
{
	DoDragDrop(new NodeDragItem(_nodeList.SelectedIndex),
		DragDropEffects.Link);
}

private void FlowChart_OnDragOver(object sender, System.Windows.Forms.DragEventArgs e)
{
	if(e.Data.GetDataPresent(NodeDragItem._GetType()))
	{
		e.Effect = DragDropEffects.Link;
	}
	else
	{
		e.Effect = DragDropEffects.None;
	}
}
 

and can't see any problems with the drag-and-drop link cursor. Could you try that with your version of flowchart.net?

You should not set the Cursor from the DragOver handler yourself, because the DoDragDrop method will change it immediately after that to the drag-and-drop link cursor.

Stoyan

Hello Eugen,

We haven't used DevExpress. Could you edit the flowcharter example and add the DockPanel there to see if drag-and-drop will stop working?

Another customer of ours had a problem with a dock panel component (maybe it was DevExpress' one, but I am not sure), that tried to save the FlowChart.RotateCursor using the Cursor.ToString method. That results in exception because Cursor.ToString works only for the .NET predefined cursor type. If a similar situation happens here before the initialization code reaches the AllowDrop = true statement, that might cause a problem. Just to check that assumption, try setting the RotateCursor to one of the .NET' predefined cursors.

Stoyan

Hi Eugen,

Perhaps you are right; currently the ShapeToolbar code that handles drag-and-drop looks like this

private void OnDocumentDragOver(object sender, System.Windows.Forms.DragEventArgs e)
{
     if (e.Data.GetDataPresent(typeof(ShapeTemplate)))
           e.Effect = DragDropEffects.Copy;
     //else
           //e.Effect = DragDropEffects.None;
}

so it seems older versions of the code set the drop-effect to none. You should still be able to work-around that by attaching your drag-and-drop event handlers after the ShapeToolbar.Document is set.

Stoyan

I too am having a peculiar issue with drag and drop with respect to DevExpress and dragging from a gridview.

Once an item is dragged over from the gridview it copies and puts a new instance of that object in the grid workspace.  however if no other item is clicked prior to moving that object the drag drop process repeats and the system creates a new instance of the just copied object. 

Any help is greatly appreciated.

On the mouse down event I call the DoDragDrop event myself. 

DoDragDrop(New NodeDragItem(_n.Copy), DragDropEffects.Copy)

where _n is my node object that inherits from flowchartnode.

So is the problem that _n always refers to the last selected item, and not the one from which dragging has started?

Stoyan