Determining the source object in a drag and drop

[Carnifex]

Hi guys,

I've been playing around with drag and drop for the first time and got it working all correctly. Except, I need a way to determine the source object that the payload came from.

Since at the moment I'm moving between listboxes and treeviews I could just include the sender in the payload (as it's text), however, if I decide later on I want to move other data as well, is there a more elegant way of finding the source object? (I guess another way would be too have a private variable that keeps track of the drag and drop operations and stores the sender)

The sender parameter obviously returns the destination object as it is the one calling the DragDrop event handler.

If anyone knows of an elegant way to determine the sender object then this would be appreciated.

Thanks.

[Edneeis]

You can use TypeOf in an expression if you think you know what it is:
If TypeOf Sender Is Gettype(Textbox) Then

Or you can get the name using either:

Sender.Gettype.Name
or
TypeName(sender)

[LeeSalter]

I also have this problem!

I have solved it by using a global variable, not very elegant, but it works.

I have this at the top of my class, in the declarations section:-

public dragSource as object

Then in the DragEnter event of my destination control I have:-

If DragSource.name <> "tree_Shortcuts_Available" Then
            e.Effect = DragDropEffects.None
        Else
            e.Effect = DragDropEffects.Copy
        End If

tree_Shortcuts_Available is the name of the only control that is allowed to drop onto this destination control.

Then in the DragDrop event I have:-

'We can only accept items from the shortcuts available
        'tree view control.
        If DragSource.name <> "tree_Shortcuts_Available" Then
            DragSource = Nothing
            Exit Sub
        End If

As I say, it's probably untidy and certainly not elegant, but it works for me.