Summary

- The SetForegroundWindow API

C# Signature:

// For Windows Mobile, replace user32.dll with coredll.dll
[DllImport("user32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool SetForegroundWindow(IntPtr hWnd);

VB Signature:

Private Declare Function SetForegroundWindow Lib "user32" (ByVal hwnd As IntPtr) As Long

User-Defined Types:

None.

Notes:

None.

Tips & Tricks:

This is especially useful for test automation to make sure the Application Under Test (AUT) retains focus before manipulating it.

This may be called several times in an automated test script, so it is best to create a method similar to the example below.

Sample Code (C#):

public static void Main(string[] args)
{
    // test code here...
    CheckAutFocus(myProcess.MainWindowHandle);
    // more test code...
}

public static void CheckAutFocus(hWnd)
{
    if (GetForegroundWindow() != hWnd)
    {
        SetForegroundWindow(hWnd);
    }
}

Sample Code (C#):

        public static bool BringWindowToTop(string windowName, bool wait)
        {
            int hWnd = FindWindow(windowName, wait);
            if (hWnd != 0)
            {
                return SetForegroundWindow((IntPtr)hWnd);
            }
            return false;
        }

        // THE FOLLOWING METHOD REFERENCES THE FindWindowAPI
        public static int FindWindow(string windowName, bool wait)
        {
            int hWnd = FindWindow(null, windowName);
            while (wait && hWnd == 0)
            {
                System.Threading.Thread.Sleep(500);
                hWnd = FindWindow(null, windowName);
            }

            return hWnd;
        }

Alternative Managed API:

The ManagedWindowsApi project (http://mwinapi.sourceforge.net) provides a static property ManagedWinapi.SystemWindow.ForegroundWindow which can be set.

Documentation

- SetForegroundWindow on MSDN

Here is an alternative Managed API to FindWindow, The article also describes a way to CloseWindow of another process like notepad, not sure if there is such thing in Win32 API, but at least you can do it in .NET! Here is the article:

http://www.mycsharpcorner.com/Post.aspx?postID=32

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