寻找在 C# 中获取重复桌面屏幕截图的最有效方法

Question

我正在寻找在 C# 中拍摄重复桌面屏幕截图的最有效方法。

我目前正在使用copyfromscreen，但它对CPU 的负担有点太大。

我想知道是否还有其他选择。

谢谢

Answer 1

尝试使用 p/Invoke GetWindowDC

Answer 2

这是我不久前使用的一些测试代码。有一段时间没有运行了，但请随意看看。希望这能让您朝着正确的方向前进。请注意，这只是一个概念证明。在投入生产之前，您需要更改一些内容（例如 Thread.Sleep）。

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Xml;
using System.Runtime.InteropServices;
using System.Drawing.Imaging;
using System.Collections;
using System.Runtime.InteropServices.ComTypes;
using System.Globalization;
using System.Reflection;

namespace ScreenShotTest
{
    class Program
    {
        [STAThreadAttribute()]
        static void Main(string[] args)
        {
            Utilities.IO.FTPFactory ftp = new Utilities.IO.FTPFactory();
            ftp.Debug = true;
            ftp.RemoteHost = "[host]";
            ftp.login();

            DateTime s = DateTime.Now;
            Console.WriteLine(DateTime.Now.ToString());
            Console.WriteLine("Friggin Test Start!");

            DA_ScreenShot.ScreenCamera camera = new DA_ScreenShot.ScreenCamera(15);
            while(true)
            {
                camera.CaptureToJpg(@"c:\tmp.jpg");
                Console.WriteLine(String.Format(@"Snapping @ {0}",DateTime.Now.ToString()));

                System.IO.FileInfo fi = new System.IO.FileInfo(@"c:\tmp.jpg");

                while(!fi.Exists)
                {
                    System.Threading.Thread.Sleep(1000);
                }

                try
                {
                    ftp.upload(@"c:\tmp.jpg");
                    ftp.deleteRemoteFile("FileShot.jpg");
                    ftp.renameRemoteFile(@"tmp.jpg",@"FileShot.jpg");
                    fi.Delete();
                }catch(Exception ex)
                {
                    Console.WriteLine(ex.ToString());
                }

                System.Threading.Thread.Sleep(5000);
            }

            ftp.close();

            TimeSpan ts = DateTime.Now - s;
            Console.WriteLine("Finished in " + ts.TotalMilliseconds.ToString() + " ms");

            camera.releaseMem();
            Console.WriteLine("Friggin Test Stop!");

        }
    }
}

namespace DA_ScreenShot
{
    /// <summary>
    /// Captures a screenshot to a local file using the System.Drawing GDI+ hooks.
    /// </summary>
    public class ScreenCamera
    {
        private System.Drawing.Size display;
        private System.Drawing.Bitmap bitmap;
        private System.Drawing.Graphics graphics;

        private ImageCodecInfo encInfo;
        private EncoderParameters encParams;
        private EncoderParameter encParam;
        private Rectangle rect;

        public ScreenCamera(long quality)
        {
            SetupGDIObjects();

            UpdateSize();

            encInfo = GetEncoderInfo("image/jpeg");
            System.Drawing.Imaging.Encoder encoder = System.Drawing.Imaging.Encoder.Quality;

            encParams = new EncoderParameters(1);
            encParam = new EncoderParameter(encoder,quality);
            encParams.Param[0] = encParam;
            rect = new Rectangle(0,0,display.Width,display.Height);
        }

        /// <summary>
        /// Sets up the objects that ScreenCamera needs to work.
        /// </summary>
        /// <returns>Successfully setup?</returns>
        private bool SetupGDIObjects()
        {
            try
            {
            display = new Size(Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height);
            bitmap = new Bitmap(display.Width, display.Height);
            graphics = System.Drawing.Graphics.FromImage(bitmap);
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
                return false;
            }
            return true;
        }

        /// <summary>
        /// Checks to see if the display size has changed and calls SetupGDIObjects
        /// if it has.
        /// </summary>
        /// <returns>Update Successful?</returns>
        private bool UpdateSize()
        {
            if (this.display.Height == Screen.PrimaryScreen.Bounds.Height &&
                this.display.Width == Screen.PrimaryScreen.Bounds.Width)
            {
                return true;
            }
            else
            {
                return SetupGDIObjects();
            }
        }

        /// <summary>
        /// Method to capture a screenshot to a local file using the System.Drawing GDI+ hooks.
        /// </summary>
        /// <param name="strFileName">The destination file to save the image to.</param>
        /// <returns>Successful?</returns>
        public bool CaptureToJpg(string strFileName)
        {
            try
            {

                graphics.CopyFromScreen(0,0,0,0, display);
                bitmap.Save(strFileName, encInfo, encParams);
            }
            catch (Exception e)
            {
                MessageBox.Show(e.ToString(), "Error!");
                return false;
            }
            return true;    
        }

        public void releaseMem()
        {
            //display = null;
            graphics.Dispose();
            graphics = null;
            bitmap.Dispose();
            bitmap = null;
        }

        private static ImageCodecInfo GetEncoderInfo(String mimeType)
        {
            int j;
            ImageCodecInfo[] encoders;
            encoders = ImageCodecInfo.GetImageEncoders();
            for(j = 0; j < encoders.Length; ++j)
            {
                if(encoders[j].MimeType == mimeType)
                    return encoders[j];
            }
            return null;
        }

    }

    public static class ScreenShot
    {
        public static void CaptureAndSave(string fileName)
        {
            uint intReturn = 0;
            NativeWIN32.INPUT structInput;
            structInput = new NativeWIN32.INPUT();
            structInput.type = (uint)1;
            structInput.ki.wScan = 0;
            structInput.ki.time = 0;
            structInput.ki.dwFlags = 0;
            structInput.ki.dwExtraInfo = 0;

            //Press Alt Key
            structInput.ki.wVk = (ushort)NativeWIN32.VK.MENU;
            intReturn = NativeWIN32.SendInput((uint)1, ref structInput, Marshal.SizeOf(structInput));

            // Key down the actual key-code
            structInput.ki.wVk = (ushort)NativeWIN32.VK.SNAPSHOT;//vk;
            intReturn = NativeWIN32.SendInput((uint)1, ref structInput, Marshal.SizeOf(structInput));


            // Key up the actual key-code
            structInput.ki.dwFlags = NativeWIN32.KEYEVENTF_KEYUP;
            structInput.ki.wVk = (ushort)NativeWIN32.VK.SNAPSHOT;//vk;
            intReturn = NativeWIN32.SendInput((uint)1, ref structInput, Marshal.SizeOf(structInput));

            //Keyup Alt
            structInput.ki.dwFlags = NativeWIN32.KEYEVENTF_KEYUP;
            structInput.ki.wVk = (ushort)NativeWIN32.VK.MENU;
            intReturn = NativeWIN32.SendInput((uint)1, ref structInput, Marshal.SizeOf(structInput));

            try
            {
                if(Clipboard.ContainsImage())
                {
                    Object data = Clipboard.GetData(DataFormats.Bitmap);;
                    Clipboard.Clear();

                    if (data != null)
                    {
                        Image image = (Image)data;
                        image.Save(fileName,System.Drawing.Imaging.ImageFormat.Jpeg);
                    }
                }
            }catch(Exception ex){Console.WriteLine(ex.Message);}
        }
    }

    internal class NativeWIN32
    {
        public const ushort KEYEVENTF_KEYUP = 0x0002;

        public enum VK : ushort
        {
            SHIFT                = 0x10,
            CONTROL              = 0x11,
            MENU                 = 0x12,
            ESCAPE               = 0x1B,
            BACK                 = 0x08,
            TAB                  = 0x09,
            RETURN               = 0x0D,
            PRIOR                = 0x21,
            NEXT                 = 0x22,
            END                  = 0x23,
            HOME                 = 0x24,
            LEFT                 = 0x25,
            UP                   = 0x26,
            RIGHT                = 0x27,
            DOWN                 = 0x28,
            SELECT               = 0x29,
            PRINT                = 0x2A,
            EXECUTE              = 0x2B,
            SNAPSHOT             = 0x2C,
            INSERT               = 0x2D,
            DELETE               = 0x2E,
            HELP                 = 0x2F,
            NUMPAD0              = 0x60,
            NUMPAD1              = 0x61,
            NUMPAD2              = 0x62,
            NUMPAD3              = 0x63,
            NUMPAD4              = 0x64,
            NUMPAD5              = 0x65,
            NUMPAD6              = 0x66,
            NUMPAD7              = 0x67,
            NUMPAD8              = 0x68,
            NUMPAD9              = 0x69,
            MULTIPLY             = 0x6A,
            ADD                  = 0x6B,
            SEPARATOR            = 0x6C,
            SUBTRACT             = 0x6D,
            DECIMAL              = 0x6E,
            DIVIDE               = 0x6F,
            F1                   = 0x70,
            F2                   = 0x71,
            F3                   = 0x72,
            F4                   = 0x73,
            F5                   = 0x74,
            F6                   = 0x75,
            F7                   = 0x76,
            F8                   = 0x77,
            F9                   = 0x78,
            F10                  = 0x79,
            F11                  = 0x7A,
            F12                  = 0x7B,
            OEM_1                = 0xBA,   // ',:' for US
            OEM_PLUS             = 0xBB,   // '+' any country
            OEM_COMMA            = 0xBC,   // ',' any country
            OEM_MINUS            = 0xBD,   // '-' any country
            OEM_PERIOD           = 0xBE,   // '.' any country
            OEM_2                = 0xBF,   // '/?' for US
            OEM_3                = 0xC0,   // '`~' for US
            MEDIA_NEXT_TRACK     = 0xB0,
            MEDIA_PREV_TRACK     = 0xB1,
            MEDIA_STOP           = 0xB2,
            MEDIA_PLAY_PAUSE     = 0xB3,
            LWIN                 = 0x5B,
            RWIN                 = 0x5C
        }

        public struct KEYBDINPUT
        {
            public ushort wVk;
            public ushort wScan;
            public uint dwFlags;
            public long time;
            public uint dwExtraInfo;
        }

        [StructLayout(LayoutKind.Explicit,Size=28)]
        public struct INPUT
        {
            [FieldOffset(0)] public uint type;
            [FieldOffset(4)] public KEYBDINPUT ki;
        }

        [DllImport("user32.dll")]
        public static extern uint SendInput(uint nInputs, ref INPUT pInputs, int cbSize);
    }
}