无边框窗体设置

#region 方法：无边框拖动窗体
        Point mouseOff;//鼠标移动位置变量
        bool RightFlag;//标签是否为左键
        private void groupMenu_MouseUp(object sender, MouseEventArgs e)
        {
            if (RightFlag)
            {
                RightFlag = false;//释放鼠标后标注为false;
            }

        }

        private void groupMenu_MouseMove(object sender, MouseEventArgs e)
        {
            if (RightFlag)
            {
                Point mouseSet = Control.MousePosition;
                mouseSet.Offset(mouseOff.X, mouseOff.Y);  //设置移动后的位置
                Location = mouseSet;
            }
        }

        private void groupMenu_MouseDown(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                mouseOff = new Point(-e.X, -e.Y); //得到变量的值
                RightFlag = true;                  //点击左键按下时标注为true;
            }
            //MouseDown_ResizeForm(this);
        }
        #endregion

#region 两边阴影
        private const int CS_DropSHADOW = 0x20000;
        private const int GCL_STYLE = (-26);
        [DllImport("user32.dll", CharSet = CharSet.Auto)]
        public static extern int SetClassLong(IntPtr hwnd, int nIndex, int dwNewLong);
        [DllImport("user32.dll", CharSet = CharSet.Auto)]
        public static extern int GetClassLong(IntPtr hwnd, int nIndex);

        private void SetShadow()
        {
            SetClassLong(this.Handle, GCL_STYLE, GetClassLong(this.Handle, GCL_STYLE) | CS_DropSHADOW);
        }
        #endregion

#region 四边阴影
        [DllImport("Gdi32.dll", EntryPoint = "CreateRoundRectRgn")]
        private static extern IntPtr CreateRoundRectRgn
                    (
                        int nLeftRect,
                        int nTopRect,
                        int nRightRect,
                        int nBottomRect,
                        int nWidthEllipse,
                        int nHeightEllipse
                     );

        [DllImport("dwmapi.dll")]
        public static extern int DwmExtendFrameIntoClientArea(IntPtr hWnd, ref MARGINS pMarInset);

        [DllImport("dwmapi.dll")]
        public static extern int DwmSetWindowAttribute(IntPtr hwnd, int attr, ref int attrValue, int attrSize);

        [DllImport("dwmapi.dll")]
        public static extern int DwmIsCompositionEnabled(ref int pfEnabled);

        private bool m_aeroEnabled;
        private const int CS_DROPSHADOW = 0x00020000;
        private const int WM_NCPAINT = 0x0085;
        private const int WM_ACTIVATEAPP = 0x001C;

        public struct MARGINS
        {
            public int leftWidth;
            public int rightWidth;
            public int topHeight;
            public int bottomHeight;
        }

        private const int WM_NCHITTEST = 0x84;
        private const int HTCLIENT = 0x1;
        private const int HTCAPTION = 0x2;

        protected override CreateParams CreateParams
        {
            get
            {
                m_aeroEnabled = CheckAeroEnabled();

                CreateParams cp = base.CreateParams;
                if (!m_aeroEnabled)
                    cp.ClassStyle |= CS_DROPSHADOW;

                return cp;
            }
        }

        private bool CheckAeroEnabled()
        {
            if (Environment.OSVersion.Version.Major >= 6)
            {
                int enabled = 0;
                DwmIsCompositionEnabled(ref enabled);
                return (enabled == 1) ? true : false;
            }
            return false;
        }

        protected override void WndProc(ref Message m)
        {
            switch (m.Msg)
            {
                case WM_NCPAINT:
                    if (m_aeroEnabled)
                    {
                        var v = 2;
                        DwmSetWindowAttribute(this.Handle, 2, ref v, 4);
                        MARGINS margins = new MARGINS()
                        {
                            bottomHeight = 1,
                            leftWidth = 1,
                            rightWidth = 1,
                            topHeight = 1
                        };
                        DwmExtendFrameIntoClientArea(this.Handle, ref margins);

                    }
                    break;
                default:
                    break;
            }
            base.WndProc(ref m);

            if (m.Msg == WM_NCHITTEST && (int)m.Result == HTCLIENT)     // drag the form
                m.Result = (IntPtr)HTCAPTION;

        }
        #endregion

原文地址：https://www.cnblogs.com/mamaxiaoling/p/8251816.html