C mouse through the form function of the implementation method

Again, this functionality requires the namespace to be loaded

using System.Runtime.InteropServices;

private const uint WS_EX_LAYERED = 0x80000;
        private const int WS_EX_TRANSPARENT = 0x20;
        private const int GWL_STYLE = (-16);
        private const int GWL_EXSTYLE = (-20);
        private const int LWA_ALPHA = 0;

        [DllImport("user32", EntryPoint = "SetWindowLong")]
        private static extern uint SetWindowLong(
        IntPtr hwnd,
        int nIndex,
        uint dwNewLong
        );

        [DllImport("user32", EntryPoint = "GetWindowLong")]
        private static extern uint GetWindowLong(
        IntPtr hwnd,
        int nIndex
        );

        [DllImport("user32", EntryPoint = "SetLayeredWindowAttributes")]
        private static extern int SetLayeredWindowAttributes(
        IntPtr hwnd,
        int crKey,
        int bAlpha,
        int dwFlags
        );

        /// <summary> 
        ///  Sets the form to have mouse penetration  
        /// </summary> 
        public void SetPenetrate()
        {
            GetWindowLong(this.Handle, GWL_EXSTYLE);
            SetWindowLong(this.Handle, GWL_EXSTYLE, WS_EX_TRANSPARENT | WS_EX_LAYERED);
            SetLayeredWindowAttributes(this.Handle, 0, 100, LWA_ALPHA);
        }