Disable MessageBox Close button [x] in C#.Net

MessageBox.Show("Are you sure, Do you want to Close this Application?","Application Name",MessageBoxButtons.YesNo);

 #region Globals



        internal const int SC_CLOSE = 0xF060;           //close button's code in windows api

        internal const int MF_GRAYED = 0x1;             //disabled button status (enabled = false)

        internal const int MF_ENABLED = 0x00000000;     //enabled button status

        internal const int MF_DISABLED = 0x00000002;    //disabled button status



        [DllImport("user32.dll")] //Importing user32.dll for calling required function

        private static extern IntPtr GetSystemMenu(IntPtr HWNDValue, bool Revert);



        /// HWND: An IntPtr typed handler of the related form

        /// It is used from the Win API "user32.dll"



        [DllImport("user32.dll")] //Importing user32.dll for calling required function again

        private static extern int EnableMenuItem(IntPtr tMenu, int targetItem, int targetStatus);



        #endregion