How do I see if my form is currently on top of the other ones?

Question

Basically, how do I tell if my program is layered above all the other ones?

Answer 1

A good solution is given by this answer to an identical question: https://stackoverflow.com/a/7162873/386091

/// 
Returns true if the current application has focus, false otherwise
public static bool ApplicationIsActivated()
{
    var activatedHandle = GetForegroundWindow();
    if (activatedHandle == IntPtr.Zero) {
        return false;       // No window is currently activated
    }

    var procId = Process.GetCurrentProcess().Id;
    int activeProcId;
    GetWindowThreadProcessId(activatedHandle, out activeProcId);

    return activeProcId == procId;
}


[DllImport("user32.dll", CharSet = CharSet.Auto, ExactSpelling = true)]
private static extern IntPtr GetForegroundWindow();

[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern int GetWindowThreadProcessId(IntPtr handle, out int processId);

The currently accepted solution by Euric doesn't work if your program shows a dialog box or has detachable windows (like if you use a windows docking framework).