winform 实现自动截全屏(屏幕分辨率)

  public class PrimaryScreen
    {
        #region Win32 API
        [DllImport("user32.dll")]
        static extern IntPtr GetDC(IntPtr ptr);
        [DllImport("gdi32.dll")]
        static extern int GetDeviceCaps(
        IntPtr hdc, // handle to DC
        int nIndex // index of capability
        );
        [DllImport("user32.dll", EntryPoint = "ReleaseDC")]
        static extern IntPtr ReleaseDC(IntPtr hWnd, IntPtr hDc);
        #endregion
        #region DeviceCaps常量
        const int HORZRES = 8;
        const int VERTRES = 10;
        const int LOGPIXELSX = 88;
        const int LOGPIXELSY = 90;
        const int DESKTOPVERTRES = 117;
        const int DESKTOPHORZRES = 118;
        #endregion
        #region 属性
        /// <summary>
        /// 获取屏幕分辨率当前物理大小
        /// </summary>
        public static Size WorkingArea
        {
            get
            {
                IntPtr hdc = GetDC(IntPtr.Zero);
                Size size = new Size();
                size.Width = GetDeviceCaps(hdc, HORZRES);
                size.Height = GetDeviceCaps(hdc, VERTRES);
                ReleaseDC(IntPtr.Zero, hdc);
                return size;
            }
        }
        /// <summary>
        /// 当前系统DPI_X 大小 一般为96
        /// </summary>
        public static int DpiX
        {
            get
            {
                IntPtr hdc = GetDC(IntPtr.Zero);
                int DpiX = GetDeviceCaps(hdc, LOGPIXELSX);
                ReleaseDC(IntPtr.Zero, hdc);
                return DpiX;
            }
        }
        /// <summary>
        /// 当前系统DPI_Y 大小 一般为96
        /// </summary>
        public static int DpiY
        {
            get
            {
                IntPtr hdc = GetDC(IntPtr.Zero);
                int DpiX = GetDeviceCaps(hdc, LOGPIXELSY);
                ReleaseDC(IntPtr.Zero, hdc);
                return DpiX;
            }
        }
        /// <summary>
        /// 获取真实设置的桌面分辨率大小
        /// </summary>
        public static Size DESKTOP
        {
            get
            {
                IntPtr hdc = GetDC(IntPtr.Zero);
                Size size = new Size();
                size.Width = GetDeviceCaps(hdc, DESKTOPHORZRES);
                size.Height = GetDeviceCaps(hdc, DESKTOPVERTRES);
                ReleaseDC(IntPtr.Zero, hdc);
                return size;
            }
        }
        /// <summary>
        /// 获取宽度缩放百分比
        /// </summary>
        public static float ScaleX
        {
            get
            {
                IntPtr hdc = GetDC(IntPtr.Zero);
                int t = GetDeviceCaps(hdc, DESKTOPHORZRES);
                int d = GetDeviceCaps(hdc, HORZRES);
                float ScaleX = (float)GetDeviceCaps(hdc, DESKTOPHORZRES) / (float)GetDeviceCaps(hdc, HORZRES);
                ReleaseDC(IntPtr.Zero, hdc);
                return ScaleX;
            }
        }
        /// <summary>
        /// 获取高度缩放百分比
        /// </summary>
        public static float ScaleY
        {
            get
            {
                IntPtr hdc = GetDC(IntPtr.Zero);
                float ScaleY = (float)(float)GetDeviceCaps(hdc, DESKTOPVERTRES) / (float)GetDeviceCaps(hdc, VERTRES);
                ReleaseDC(IntPtr.Zero, hdc);
                return ScaleY;
            }
        }
        #endregion
    }

 /// <summary>
        /// 截取屏
        /// </summary>
        /// <returns></returns>
        public static bool ScreenCapture(string savePath, ImageFormat format)
        {
            try
            {
                // 获得当前屏幕的分辨率
                var size = PrimaryScreen.DESKTOP;
                int iWidth = size.Width;
                int iHeight = size.Height;
                Bitmap bitmap = new Bitmap(iWidth, iHeight);
                Graphics g = Graphics.FromImage(bitmap);
                g.CopyFromScreen(Point.Empty, Point.Empty, new Size(iWidth, iHeight));
                System.Threading.Thread.Sleep(50);
                if ("" != savePath)
                {
                    bitmap.Save(savePath, format);
                }
                bitmap.Dispose();
                return true;
            }
            catch (System.Exception ex)
            {
                MessageBox.Show("抓图失败！");
                return false;
            }
        }