Here is one way to get the topmost form that uses Win32 (not very elegant, but it works):
public const int GW_HWNDNEXT = 2; // The next window is below the specified window
public const int GW_HWNDPREV = 3; // The previous window is above
[DllImport("user32.dll")]
static extern IntPtr GetTopWindow(IntPtr hWnd);
[DllImport("user32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool IsWindowVisible(IntPtr hWnd);
[DllImport("user32.dll", CharSet = CharSet.Auto, EntryPoint = "GetWindow", SetLastError = true)]
public static extern IntPtr GetNextWindow(IntPtr hwnd, [MarshalAs(UnmanagedType.U4)] int wFlag);
/// <summary>
/// Searches for the topmost visible form of your app in all the forms opened in the current Windows session.
/// </summary>
/// <param name="hWnd_mainFrm">Handle of the main form</param>
/// <returns>The Form that is currently TopMost, or null</returns>
public static Form GetTopMostWindow(IntPtr hWnd_mainFrm)
{
Form frm = null;
IntPtr hwnd = GetTopWindow((IntPtr)null);
if (hwnd != IntPtr.Zero)
{
while ((!IsWindowVisible(hwnd) || frm == null) && hwnd != hWnd_mainFrm)
{
// Get next window under the current handler
hwnd = GetNextWindow(hwnd, GW_HWNDNEXT);
try
{
frm = (Form)Form.FromHandle(hwnd);
}
catch
{
// Weird behaviour: In some cases, trying to cast to a Form a handle of an object
// that isn't a form will just return null. In other cases, will throw an exception.
}
}
}
return frm;
}