How to bring my application to the front?

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孤城傲影
孤城傲影 2020-12-08 15:32

I know all the reasons why it is a bad idea. I dislike it if an application steals input focus, but this is for purely personal use and I want it to happen; it will not dist

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  •  無奈伤痛
    2020-12-08 15:58

    I am doing something similar in one of my applications and this function works for me in xp/vista/w7:

    function ForceForegroundWindow(hwnd: THandle): Boolean;
    const
      SPI_GETFOREGROUNDLOCKTIMEOUT = $2000;
      SPI_SETFOREGROUNDLOCKTIMEOUT = $2001;
    var
      ForegroundThreadID: DWORD;
      ThisThreadID: DWORD;
      timeout: DWORD;
    begin
      if IsIconic(hwnd) then ShowWindow(hwnd, SW_RESTORE);
    
      if GetForegroundWindow = hwnd then Result := True
      else
      begin
        // Windows 98/2000 doesn't want to foreground a window when some other
        // window has keyboard focus
    
        if ((Win32Platform = VER_PLATFORM_WIN32_NT) and (Win32MajorVersion > 4)) or
          ((Win32Platform = VER_PLATFORM_WIN32_WINDOWS) and
          ((Win32MajorVersion > 4) or ((Win32MajorVersion = 4) and
          (Win32MinorVersion > 0)))) then
        begin
          Result := False;
          ForegroundThreadID := GetWindowThreadProcessID(GetForegroundWindow, nil);
          ThisThreadID := GetWindowThreadPRocessId(hwnd, nil);
          if AttachThreadInput(ThisThreadID, ForegroundThreadID, True) then
          begin
            BringWindowToTop(hwnd); // IE 5.5 related hack
            SetForegroundWindow(hwnd);
            AttachThreadInput(ThisThreadID, ForegroundThreadID, False);
            Result := (GetForegroundWindow = hwnd);
          end;
          if not Result then
          begin
            // Code by Daniel P. Stasinski
            SystemParametersInfo(SPI_GETFOREGROUNDLOCKTIMEOUT, 0, @timeout, 0);
            SystemParametersInfo(SPI_SETFOREGROUNDLOCKTIMEOUT, 0, TObject(0),
              SPIF_SENDCHANGE);
            BringWindowToTop(hwnd); // IE 5.5 related hack
            SetForegroundWindow(hWnd);
            SystemParametersInfo(SPI_SETFOREGROUNDLOCKTIMEOUT, 0, TObject(timeout), SPIF_SENDCHANGE);
          end;
        end
        else
        begin
          BringWindowToTop(hwnd); // IE 5.5 related hack
          SetForegroundWindow(hwnd);
        end;
    
        Result := (GetForegroundWindow = hwnd);
      end;
    end;
    

    Another solution is not to steal focus and just put the window TOPMOST in the z buffer:

    procedure ForceForegroundNoActivate(hWnd : THandle);
    
    begin
     if IsIconic(Application.Handle) then
      ShowWindow(Application.Handle, SW_SHOWNOACTIVATE);
     SetWindowPos(hWnd, HWND_TOPMOST, 0, 0, 0, 0, SWP_NOSIZE or SWP_NOACTIVATE or SWP_NOMOVE);
     SetWindowPos(hWnd, HWND_NOTOPMOST, 0, 0, 0, 0, SWP_NOSIZE or SWP_NOACTIVATE or SWP_NOMOVE);
    end;
    

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