How do I bring an unmanaged application window to front, and make it the active window for (simulated) user input

Question

I am assuming I need to use pinvoke but I am not sure which function calls are needed.

Scenario: a legacy application will be running, I will have Handle for that application.

I need to:

bring that application to the top (in front of all other windows)
make it the active window

Which Windows function calls are needed?

user703016 · Accepted Answer · 2014-03-20T09:20:58.263

16

If you don't have a handle to the window, use this before :

[DllImport("user32.dll", SetLastError = true)]
static extern IntPtr FindWindow(string lpClassName, string lpWindowName);

Now assuming you have a handle to the application window :

[DllImport("user32.dll", SetLastError = true)]
static extern bool SetForegroundWindow(IntPtr hWnd);

This will make the taskbar flash if another window has keyboard focus.

If you want to force the window to come to the front, use ForceForegroundWindow (sample implementation).

edited Mar 20 '14 at 09:20

answered Jun 03 '11 at 14:20

user703016

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SetForegroundWindow seems to do what I need so far however I get error when trying to call ForceForegroundWindow ("Unable to find an entry point named 'ForceForegroundWindow' in DLL 'user32.dll'.") – Gerald Davis Jun 03 '11 at 15:07
In my case, I had to use 'BringWindowToTop' in addition to this. ForceForegroundWindow solved my problem beautifully. Thanks! – Robert Jeppesen Jun 05 '12 at 20:10
Is this the ForceForegroundWindow code you mentioned: http://pastebin.com/zkdZvKuG ? – DDA Mar 07 '14 at 18:16
@user1681490 Sadly I don't remember what the original code was, but it's possible, yes. – user703016 Mar 07 '14 at 19:28
@ParkYoung-Bae how would I include/use the WinAPI class in C#? – andreas Jan 04 '15 at 00:52
For what it's worth, I found the ForceForegroundWindow full example here: https://shlomio.wordpress.com/2012/09/04/solved-setforegroundwindow-win32-api-not-always-works/ via http://pinvoke.net/default.aspx/user32/SetForegroundWindow.html I can't seem to get it to work in Win 10 v1903, but it could just be the application I'm working to bring forward. – cvocvo Nov 20 '19 at 18:44

score 15 · Answer 2 · answered Jun 07 '11 at 20:07

This has proved to be extremely reliable. The ShowWindowAsync function is specifically designed for windows created by a different thread. The SW_SHOWDEFAULT makes sure the window is restored prior to showing, then activating.

    [DllImport("user32.dll", SetLastError = true)]
    internal static extern bool ShowWindowAsync(IntPtr windowHandle, int nCmdShow);

    [DllImport("user32.dll", SetLastError = true)]
    internal static extern bool SetForegroundWindow(IntPtr windowHandle);

Then making the calls:

ShowWindowAsync(windowHandle, SW_SHOWDEFAULT);
ShowWindowAsync(windowHandle, SW_SHOW);
SetForegroundWindow(windowHandle);

Works like a charm while every other code I tried failed. – TH Todorov Sep 04 '15 at 10:30 — TH Todorov, Sep 04 '15 at 10:30

score 12 · Answer 3 · answered Jan 30 '12 at 05:15

    [DllImport("user32.dll")]
    public static extern bool ShowWindowAsync(HandleRef hWnd, int nCmdShow);
    [DllImport("user32.dll")]
    public static extern bool SetForegroundWindow(IntPtr WindowHandle);
    public const int SW_RESTORE = 9;

ShowWindowAsync method is used to show the minimized application and SetForegroundWindow method is used to bring on front the back application.

you can use these methods as i used in my application to bring the skype infront of my application. on button click

private void FocusSkype()
    {
        Process[] objProcesses = System.Diagnostics.Process.GetProcessesByName("skype");
        if (objProcesses.Length > 0)
        {
            IntPtr hWnd = IntPtr.Zero;
            hWnd = objProcesses[0].MainWindowHandle;
            ShowWindowAsync(new HandleRef(null,hWnd), SW_RESTORE);
             SetForegroundWindow(objProcesses[0].MainWindowHandle);
        }
    }

How do I bring an unmanaged application window to front, and make it the active window for (simulated) user input

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