[SOLVED] Drag and drop text into SynEdit control

Drag and drop text into SynEdit control

I have a TSynEdit control on a form and I want to drag and drop the focused node text from a TVirtualStringTree. I would like it to behave in the same way as when you drag and drop the highlighted text within the TSynEdit control:

As you drag over the TSynEdit, the caret should mark the current drop position.
When the text is dropped, it should replace any text that is currently highlighted.
The drop position should handle tabs correctly.

I have looked at the code in the TSynEdit DragOver event, but it uses several variables and procedures that I can't access in a descendant class as they are declared private.

I have checked all the TSynEdit demos and can't find one that addresses my needs.

Anybody managed to do this successfully?

Solution

I think that you can manage to reach your goal by assigning two events to your editor: DragOver/DragDrop.

1/ you test the validity in the DragOver event, you also move the caret by calling GetPositionOfMouse

Procedure TForm1.EditorDragOver(Sender,Source: TObject;X,Y: Integer; State: TDragState; Var Accept: Boolean);
Var
  LCoord: TBufferCoord;
  LMemo: TSynMemo;
Begin
  LMemo := TSynMemo(Sender);
  // In your case you would rather test something with your tree...
  Accept := Clipboard.AsText <> '';
  // "As you drag over the TSynEdit, the caret should mark the current drop position": OK
  If LMemo.GetPositionOfMouse(LCoord) Then
    LMemo.CaretXY := LCoord;
End;

2/ You use the editor commands in the DragDrop event, to clear the selection and to insert chars

Procedure TForm1.EditorDragDrop(Sender, Source: TObject; X,Y: Integer);
Var
  LMemo: TSynMemo;
Begin
  LMemo := TSynMemo(Sender);
  // "When the text is dropped, it should replace any text that is currently highlighted." : OK
  If LMemo.SelAvail Then
    LMemo.ExecuteCommand( ecDeleteChar , #0, Nil );
  // Paste, same comment as previously, here it's just an example...
  LMemo.ExecuteCommand( ecPaste, #0, Nil );
End;

This would have to be a bit tweaked according to your context.