Why doesn't my form receive WM_DropFiles when files are dropped on it?

Question

I am using Embarcadero RAD Studio XE to develop an application. I am trying catch the file(s) drag and drop to the application with the following code

TMainForm = class(TForm)
public:
  procedure WMDropFiles(var Msg: TWMDropFiles); message WM_DROPFILES;
end;

procedure TMainForm.FormCreate(Sender: TObject);
begin
  DragAcceptFiles(Self.Handle, True);
end;

procedure TMainForm.FormDestroy(Sender: TObject);
begin
  DragAcceptFiles(Self.Handle, False);
end;

procedure TMainForm.WMDropFiles(var Msg: TWMDropFiles);
begin
  inherited;
  showmessage('catch here');
  // some code to handle the drop files here
  Msg.Result := 0;
end;

This code complied without problem. Also, when I drag and drop files, the cursor show that the status changed to drag and drop but after things dropped, nothing happen (no message shown too). Is that anything wrong with that?

Answer 1

in TForm.Create use two lines

ChangeWindowMessageFilter (WM_DROPFILES, MSGFLT_ADD);

ChangeWindowMessageFilter (WM_COPYGLOBALDATA, MSGFLT_ADD);

that's all