c# - WebBrowser.DrawToBitmap() 或其他方法？

Question

我正在 try catch WebBrowser 控件的内容。 DrawToBitmap() 可以完美运行，但 WebBrowser 控件的文档不支持它。我一直在尝试寻找另一种方法来捕获 WebBrowser 控件的内容并将它们保存到本地镜像文件。

有没有人有任何解决方法或其他方法来将 WebBrowser 控件的内容保存到本地镜像文件？

Answer 1

Control.DrawToBitmap 并不总是有效，因此我求助于以下提供更一致结果的 native API 调用:

实用程序类。调用 Utilities.CaptureWindow(Control.Handle) 捕获特定控件:

public static class Utilities
{
    public static Image CaptureScreen()
    {
        return CaptureWindow(User32.GetDesktopWindow());
    }

    public static Image CaptureWindow(IntPtr handle)
    {

        IntPtr hdcSrc = User32.GetWindowDC(handle);

        RECT windowRect = new RECT();
        User32.GetWindowRect(handle, ref windowRect);

        int width = windowRect.right - windowRect.left;
        int height = windowRect.bottom - windowRect.top;

        IntPtr hdcDest = Gdi32.CreateCompatibleDC(hdcSrc);
        IntPtr hBitmap = Gdi32.CreateCompatibleBitmap(hdcSrc, width, height);

        IntPtr hOld = Gdi32.SelectObject(hdcDest, hBitmap);
        Gdi32.BitBlt(hdcDest, 0, 0, width, height, hdcSrc, 0, 0, ApiConstants.SRCCOPY);
        Gdi32.SelectObject(hdcDest, hOld);
        Gdi32.DeleteDC(hdcDest);
        User32.ReleaseDC(handle, hdcSrc);

        Image image = Image.FromHbitmap(hBitmap);
        Gdi32.DeleteObject(hBitmap);

        return image;
    }
}

Gdi32 类:

public class Gdi32
{
    [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);
}

User32 类:

public static class User32
{
    [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 GetWindowRect(IntPtr hWnd, ref RECT rect);
    [DllImport("user32.dll")]
    public static extern IntPtr ReleaseDC(IntPtr hWnd, IntPtr hDC);
}

使用的常量:

    public const int SRCCOPY = 13369376;

使用的结构:

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

友好的控件扩展方法:

public static class ControlExtensions
{
    public static Image DrawToImage(this Control control)
    {
        return Utilities.CaptureWindow(control.Handle);
    }
}

这是我的 CC.Utilities 的代码片段项目，我专门编写它以从 WebBrowser 控件截取屏幕截图。