Question

我正在尝试捕获C＃中的表单屏幕截图，我正在使用以下代码。代码正常工作，但仅当表单在每个其他应用程序的顶部时。如果表格低于其他形式，那么它不是被捕获的形式。

有人知道要执行的任何代码吗？

由于

    Public Function GetScreenShot(F As Form) As Bitmap
        Dim Bounds As Rectangle = F.Bounds

        Dim Bitmap As Bitmap = New Bitmap(Bounds.Width, Bounds.Height)
        Dim G As Graphics = Graphics.FromImage(Bitmap)
        G.CopyFromScreen(New Point(Bounds.Left, Bounds.Top), Point.Empty, Bounds.Size)

        Return Bitmap
    End Function

Answer 1

这是一个工作副本，我创建了一个Windows窗体并从另一个应用程序中截取屏幕截图并将其保存在磁盘上。

using System;
using System.Diagnostics;
using System.Drawing;
using System.Drawing.Imaging;
using System.Runtime.InteropServices;
using System.Windows.Forms;

namespace ScreenshotApp
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        public void TakeScreenShot()
        {
            Process p = Process.GetProcessById(16416); //modify to use PID or use GetProcessByName
            IntPtr handle = p.MainWindowHandle;
            SomeImageThingy.CaptureWindow(handle);
        }

        private void button1_Click(object sender, System.EventArgs e)
        {
            TakeScreenShot();
        }
    }

    public class User32
    {
        [StructLayout(LayoutKind.Sequential)]
        public struct RECT
        {
            public int left;
            public int top;
            public int right;
            public int bottom;
        }

        [DllImport("user32.dll")]
        public static extern IntPtr GetDesktopWindow();
        [DllImport("user32.dll")]
        public static extern IntPtr GetWindowDC(IntPtr hWnd);
        [DllImport("user32.dll")]
        public static extern IntPtr ReleaseDC(IntPtr hWnd, IntPtr hDC);
        [DllImport("user32.dll")]
        public static extern IntPtr GetWindowRect(IntPtr hWnd, ref RECT rect);
    }

    public class GDI32
    {
        public const int SRCCOPY = 0x00CC0020; // BitBlt dwRop parameter

        [DllImport("gdi32.dll")]
        public static extern bool BitBlt(IntPtr hObject, int nXDest, int nYDest,
            int nWidth, int nHeight, IntPtr hObjectSource,
            int nXSrc, int nYSrc, int dwRop);
        [DllImport("gdi32.dll")]
        public static extern IntPtr CreateCompatibleBitmap(IntPtr hDC, int nWidth,
            int nHeight);
        [DllImport("gdi32.dll")]
        public static extern IntPtr CreateCompatibleDC(IntPtr hDC);
        [DllImport("gdi32.dll")]
        public static extern bool DeleteDC(IntPtr hDC);
        [DllImport("gdi32.dll")]
        public static extern bool DeleteObject(IntPtr hObject);
        [DllImport("gdi32.dll")]
        public static extern IntPtr SelectObject(IntPtr hDC, IntPtr hObject);
    }

    public static class SomeImageThingy
    {
        public static Image CaptureWindow(IntPtr handle)
        {
            // get te hDC of the target window
            IntPtr hdcSrc = User32.GetWindowDC(handle);
            // get the size
            User32.RECT windowRect = new User32.RECT();
            User32.GetWindowRect(handle, ref windowRect);
            int width = windowRect.right - windowRect.left;
            int height = windowRect.bottom - windowRect.top;
            // create a device context we can copy to
            IntPtr hdcDest = GDI32.CreateCompatibleDC(hdcSrc);
            // create a bitmap we can copy it to,
            // using GetDeviceCaps to get the width/height
            IntPtr hBitmap = GDI32.CreateCompatibleBitmap(hdcSrc, width, height);
            // select the bitmap object
            IntPtr hOld = GDI32.SelectObject(hdcDest, hBitmap);
            // bitblt over
            GDI32.BitBlt(hdcDest, 0, 0, width, height, hdcSrc, 0, 0, GDI32.SRCCOPY);
            // restore selection
            GDI32.SelectObject(hdcDest, hOld);
            // clean up 
            GDI32.DeleteDC(hdcDest);
            User32.ReleaseDC(handle, hdcSrc);

            // get a .NET image object for it
            Image img = Image.FromHbitmap(hBitmap);
            img.Save("capture.png", ImageFormat.Png);
            // free up the Bitmap object
            GDI32.DeleteObject(hBitmap);

            return img;
        }
    }
}

Answer 2

您可以使用内置的方式将整个表单绘制到位图：

F.DrawToBitmap(Bitmap, F.ClientRectangle);

其中F是表单的实例

Answer 3

这是因为您的表单位于z顺序的窗口下方，这使得它们覆盖表单区域并使其不被捕获。您可以做的是使用Form.TopMost将表单置于最前面，然后重置它以快速修复问题：

Public Function GetScreenShot(F As Form) As Bitmap
    'Bring the form to top and reset afterwards        
    F.TopMost = True
    F.TopMost = False

    /.../
End Function

如何在C＃中获取winform屏幕截图？

3 个答案: