Dynamic Win32 API Call + Anti User-mode hooking [C#]

// http://codecav.blogspot.in/

IntPtr title = Marshal.StringToHGlobalAnsi("Title");
            IntPtr msg = Marshal.StringToHGlobalAnsi("Message");

            IntPtr[] args = {IntPtr.Zero, msg, title, (IntPtr) (MessageBoxButtons.YesNo)};

            IntPtr retValue;
            bool res = DynamicApi.TryExecute("user32.dll", "MessageBoxA", args, out retValue);

            if (res)
            {
                MessageBox.Show("Return value: " + retValue.ToString("D"));
            }

            Marshal.FreeHGlobal(title);
            Marshal.FreeHGlobal(msg);