Delphi Determine file version

Pass the full file name of your EXE to this function, and it will return a string like: 2.1.5.9, or whatever your version # is.

function GetFileVersion(exeName : string): string;
const
  c_StringInfo = 'StringFileInfo\040904E4\FileVersion';
var
  n, Len : cardinal;
  Buf, Value : PChar;
begin
  Result := '';
  n := GetFileVersionInfoSize(PChar(exeName),n);
  if n > 0 then begin
    Buf := AllocMem(n);
    try
      GetFileVersionInfo(PChar(exeName),0,n,Buf);
      if VerQueryValue(Buf,PChar(c_StringInfo),Pointer(Value),Len) then begin
        Result := Trim(Value);
      end;
    finally
      FreeMem(Buf,n);
    end;
  end;
end;

After defining that, you can use it to set your form's caption like so:

procedure TForm1.FormShow(Sender: TObject);
begin
  //ParamStr(0) is the full path and file name of the current application
  Form1.Caption := Form1.Caption + ' version ' + GetFileVersion(ParamStr(0));
end;

This doesn't work unless your locale is $0409 (United States English) - not a reliable assumption