.NET 4 single application instance

Question

I often write .net applications that only support one instance. Formerly I used .net-remoting and now WCF to detect if already an instance of my app is running and giving th

Answer 1

I use a Mutex, and FindWindow to do this.

Concerning your comment on another answer:
For information on Local and Global mutexes in Terminal Services, follow this link.

Terminal Services client processes can use object names with a "Global\" or "Local\" prefix to explicitly create an object in the global or session name space.

This is the code I use to activate the window:

[DllImport("user32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool IsIconic(IntPtr hWnd);

[DllImport("user32.dll")]
static extern bool ShowWindow(IntPtr hWnd, int nCmdShow);
private const int SH_SHOW = 5;
private const int SH_RESTORE = 9;

[DllImport("user32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool SetForegroundWindow(IntPtr hWnd);

public void Activate(IntPtr hwnd)
{
    if (IsIconic(hwnd))
        ShowWindow(hwnd, SH_RESTORE);
    else
        ShowWindow(hwnd, SH_SHOW);

    SetForegroundWindow(hwnd);
}