[nonVCL] Textlänge & GetWindowText, ExtTextOut Problem

[Luckie]

Delphi-Quellcode:

procedure TForm1.Button1Click(Sender: TObject);
var
  Buffer            : PChar;
  len               : Integer;
begin
  len := GetWindowTextLength(Handle);
  if len > 0 then
  begin
    try
      GetMem(Buffer, len);
      GetWindowText(Handle, Buffer, len);
      TextOut(Canvas.Handle, 10, 10, Buffer, len);
    finally
      FreeMem(Buffer);
    end;
  end
  else
    ShowMessage(SysErrorMessage(GetLastError));
end;

Aber beachte:

Zitat:

GetWindowTextLength cannot retrieve the length of the text of an edit control in another application.

Und:

Zitat:

Under certain conditions, the GetWindowTextLength function may return a value that is larger than the actual length of the text. [..] It can also occur when an application uses the ANSI version of GetWindowTextLength with a window whose window procedure is Unicode, or the Unicode version of GetWindowTextLength with a window whose window procedure is ANSI.

Zitat:

To obtain the exact length of the text, use the WM_GETTEXT, LB_GETTEXT, or CB_GETLBTEXT messages, or the GetWindowText function.

Und zu GetWindowText:

Zitat:

This function cannot retrieve the text of an edit control in another application.