C#实现窗体阴影效果

       #region 窗体边框阴影效果变量申明
        const int CS_DropSHADOW = 0x20000;
        const int GCL_STYLE = (-26);
        //声明Win32 API
        [DllImport("user32.dll", CharSet =CharSet.Auto)]
        public static extern int SetClassLong(IntPtr hwnd, int nIndex, intdwNewLong);
        [DllImport("user32.dll", CharSet =CharSet.Auto)]
        public static extern int GetClassLong(IntPtr hwnd, intnIndex);
        #endregion
        publicLoginForm()
        {
            SetClassLong(this.Handle, GCL_STYLE, GetClassLong(this.Handle, GCL_STYLE) | CS_DropSHADOW); //API函数加载，实现窗体边框阴影效果
        }