[DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
    public static extern int MessageBoxW(IntPtr hWnd, String text, String caption, uint type);

    //We need to declare a delegate that matches the prototype of the hooked function
    [UnmanagedFunctionPointer(CallingConvention.StdCall,CharSet=CharSet.Unicode)]
    delegate int MessageBoxWDelegate(IntPtr hWnd, string text, string caption, uint type);

    //A variable to store the original function so that we can call
    //within our detoured MessageBoxW handler
    MessageBoxWDelegate MessageBoxW_orig;

    //Our actual detour handler function
    int MessageBoxW_Detour(IntPtr hWnd, string text, string caption, uint type) {
        return MessageBoxW_orig(hWnd, "HOOKED: " + text, caption, type);
    }

    void ChangeMessageBoxMessage() {

		using (HookEngine engine = new HookEngine()) {

			MessageBoxW_orig = engine.CreateHook("user32.dll", "MessageBoxW", new MessageBoxWDelegate(MessageBoxW_Detour));
			engine.EnableHooks();

			//Call the PInvoke import to test our hook is in place
			MessageBoxW(IntPtr.Zero, "Text", "Caption", 0);
		}
    }