Scott Hollows – One Line At A Time

Simple example of converting a window handle (HWND data type) to a string in a Delphi VCL program

cardinal(vMyWindowHandle).ToString

This uses the WinApi.Windows unit

Example

Show the window handle of the foreground window

procedure TForm1.Button1Click(Sender: TObject);
var
   vMyWindowHandle : HWND;
begin
   vMyWindowHandle := GetForegroundWindow();  // get top most window

   ShowMessage ('Window handle is '
               + cardinal(vMyWindowHandle).ToString
               );
end;

Use your own own conversion function

The conversion of a handle to cardinal number type is not guarenteed to work on all future versions of Windows.  For a “best practise” approach you should wrap the conversion code into a function so you can change the conversion code if needed,

function HandleToString (aHandle : HWND) : string;
begin
  result := cardinal(aHandle).ToString;
end;

procedure TForm1.Button1Click(Sender: TObject);
var
 vMyWindowHandle : cardinal; // uses WinApi.Windows
begin
 vMyWindowHandle := GetForegroundWindow();
 ShowMessage ('The window handle is ' + HandleToString(vMyWindowHandle));
end;

Tested Delphi Versions

Tested ok on Delphi 10.1 on Windows 7 32 bit and Windows 10 64 bit.
It should work with many other version of Delphi and Windows

Im sure this would not work prior to Delphi 2005 as it uses a record helper that was introduced in that version of Delphi.

If you can verify any other versions of Delphi / Windows please post a comment below

Other Conversion Methods

Try IntToStr and Format

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About Me

• Oracle & Delphi software developer based in Perth, Western Australia
• Australian Delphi User Group – President and WA meeting organizer
• Australian Oracle User Group – WA State Committee Member
• Available to do remote presentations to user groups on Delphi and Oracle topics