截取所有可见应用程序和表单的多个桌面的屏幕截图

我尝试了GetDesktopWindow()函数，但它不能正常工作。

当然不是。

GetDesktopWindow函数返回一个句柄到桌面窗口。它与捕获该窗口的图像没有任何关系。

此外，桌面窗口和"整个屏幕"不是一回事。它专门指桌面窗口。请参阅本文了解更多信息，以及滥用该函数返回的句柄可能导致的错误。

我正在使用一个系统，该系统有4个输出(监视器)，每个输出1280x1024(例如)。我需要整个桌面和所有打开的应用程序的截图。

这在。net框架中使用Graphics.CopyFromScreen方法是相对简单的。您甚至不需要执行任何P/Invoke!

在这种情况下唯一的技巧是确保传递适当的维度。因为你有4个显示器，所以只传递主屏幕的尺寸是行不通的。您需要传递整个虚拟屏幕的尺寸，其中包含所有显示器。通过查询SystemInformation.VirtualScreen属性来检索它，该属性返回虚拟屏幕的边界。如文档所示，这是多监视器系统上整个桌面的边界。

示例代码:

// Determine the size of the "virtual screen", which includes all monitors.
int screenLeft   = SystemInformation.VirtualScreen.Left;
int screenTop    = SystemInformation.VirtualScreen.Top;
int screenWidth  = SystemInformation.VirtualScreen.Width;
int screenHeight = SystemInformation.VirtualScreen.Height;
// Create a bitmap of the appropriate size to receive the screenshot.
using (Bitmap bmp = new Bitmap(screenWidth, screenHeight))
{
    // Draw the screenshot into our bitmap.
    using (Graphics g = Graphics.FromImage(bmp))
    {
        g.CopyFromScreen(screenLeft, screenTop, 0, 0, bmp.Size);
    }
    // Do something with the Bitmap here, like save it to a file:
    bmp.Save(savePath, ImageFormat.Jpeg);
}

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编辑:

请在非主线程线程中的WPF应用程序中检查您的解决方案。我试过了。它不工作!

嗯，我没有在问题上看到WPF标签，也没有在正文中提到。

不过没关系。我发布的代码在WPF应用程序中工作得很好，只要您添加适当的引用和using声明。你需要System.Windows.Forms和System.Drawing。可能会有一种更wpf风格的方式来做到这一点，不需要依赖这些WinForms程序集，但我不知道它是什么。

它甚至可以在另一个线程上工作。这里没有任何东西需要UI线程。

是的，我测试过了。下面是我的完整测试代码:

using System.Windows;
using System.Windows.Forms;   // also requires a reference to this assembly
using System.Drawing;         // also requires a reference to this assembly
using System.Drawing.Imaging;
using System.Threading;
public partial class MainWindow : Window
{
   public MainWindow()
   {
      InitializeComponent();
   }
   private void button1_Click(object sender, RoutedEventArgs e)
   {
      // Create a new thread for demonstration purposes.
      Thread thread = new Thread(() =>
      {
         // Determine the size of the "virtual screen", which includes all monitors.
         int screenLeft   = SystemInformation.VirtualScreen.Left;
    int screenTop    = SystemInformation.VirtualScreen.Top;
    int screenWidth  = SystemInformation.VirtualScreen.Width;
    int screenHeight = SystemInformation.VirtualScreen.Height;
         // Create a bitmap of the appropriate size to receive the screenshot.
         using (Bitmap bmp = new Bitmap(screenWidth, screenHeight))
         {
            // Draw the screenshot into our bitmap.
            using (Graphics g = Graphics.FromImage(bmp))
            {
               g.CopyFromScreen(screenLeft, screenTop, 0, 0, bmp.Size);
            }
            // Do something with the Bitmap here, like save it to a file:
            bmp.Save("G:''TestImage.jpg", ImageFormat.Jpeg);
         }
      });
      thread.SetApartmentState(ApartmentState.STA);
      thread.Start();
   }
}

我创建了一个小助手，因为我今天需要这个案例并尝试了许多不同的函数。与监视器的数量无关，您可以将其保存为磁盘上的文件，或者使用以下代码块将其存储在db中的二进制字段中。

ScreenShotHelper.cs

using System.ComponentModel;//This namespace is required for only Win32Exception. You can remove it if you are catching exceptions from another layer.
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
namespace Company.Core.Helpers.Win32 {
    public static class ScreenShotHelper {
        private static Bitmap CopyFromScreen(Rectangle bounds) {
            try {
                var image = new Bitmap(bounds.Width, bounds.Height);
                using var graphics = Graphics.FromImage(image);
                graphics.CopyFromScreen(Point.Empty, Point.Empty, bounds.Size);
                return image;
            }
            catch(Win32Exception) {//When screen saver is active
                return null;
            }
        }
        public static Image Take(Rectangle bounds) {
            return CopyFromScreen(bounds);
        }
        public static byte[] TakeAsByteArray(Rectangle bounds) {
            using var image = CopyFromScreen(bounds);
            using var ms = new MemoryStream();
            image.Save(ms, ImageFormat.Png);
            return ms.ToArray();
        }   
        public static void TakeAndSave(string path, Rectangle bounds, ImageFormat imageFormat) {
            using var image = CopyFromScreen(bounds);
            image.Save(path, imageFormat);
        }
    }
}

用法-二进制字段

var bounds = new Rectangle();
bounds = Screen.AllScreens.Aggregate(bounds, (current, screen) 
                           => Rectangle.Union(current, screen.Bounds));
_card.ScreenShot = Convert.ToBase64String(ScreenShotHelper.TakeAsByteArray(bounds));

使用率-磁盘文件

var bounds = new Rectangle();
bounds = Screen.AllScreens.Aggregate(bounds, (current, screen) 
                           => Rectangle.Union(current, screen.Bounds));
ScreenShotHelper.TakeAndSave(@"d:'screenshot.png", bounds, ImageFormat.Png);