public partial class Form1 : Form

    {

        int en;

        public struct MARGINS

        {

            public int m_Left;

            public int m_Right;

            public int m_Top;

            public int m_Buttom;

        };

        [DllImport("dwmapi.dll")]

        private static extern void DwmIsCompositionEnabled(ref int enabledptr);

        [DllImport("dwmapi.dll")]

        private static extern void DwmExtendFrameIntoClientArea(IntPtr hWnd, ref MARGINS margin);

        public Form1()

        {

            InitializeComponent();

            en = ;

            MARGINS mg = new MARGINS(); //定义透明扩展区域的大小，这里全部-1，即全部透明

            mg.m_Buttom = -;

            mg.m_Left = -;

            mg.m_Right = -;

            mg.m_Top = -;

            //判断是否Vista及以上的系统

            if (System.Environment.OSVersion.Version.Major >= )

            {

                DwmIsCompositionEnabled(ref en);    //检测Aero是否为打开

                if (en > )

                {

                    DwmExtendFrameIntoClientArea(this.Handle, ref mg);   //透明

                }

            }

            this.Paint += new PaintEventHandler(Form1_Paint);

        }

        private void Form1_Paint(object sender, PaintEventArgs e)

        {

            if (en > )

            {

                Graphics g = e.Graphics;

                SolidBrush bsh = new SolidBrush(Color.Black);

                g.FillRectangle(bsh, this.ClientRectangle);

                bsh.Dispose();

            }

        }

        private void Form1_Load(object sender, EventArgs e)

        {

        }

    }