WebBrowser.DrawToBitmap（）或其他方法？ [英] WebBrowser.DrawToBitmap() or other methods?

问题描述

我试图捕捉WebBrowser控件的内容。 DrawToBitmap（）将很好地工作，但它不支持在WebBrowser控件文件。我一直在试图寻找另一种方式来捕捉WebBrowser控件的内容，并将其保存到本地的图像文件。

I am trying to capture the content of the WebBrowser control. DrawToBitmap() would work perfectly, but it is not supported in documentation for the WebBrowser control. I have been trying to find another way to capture the contents of the WebBrowser control and save them to a local image file.

没有人有任何解决方法或其他方法来WebBrowser控件的内容保存到本地的图像文件？

Does anyone have any workarounds or other methods to save the contents of the WebBrowser control to a local image file?

推荐答案

在Control.DrawToBitmap并不总是工作，所以我使出提供更一致的结果下面的原生API调用：

The Control.DrawToBitmap doesn't always work so I resorted to the following native API calls that provide more consistent results:

该实用程序类。呼叫Utilities.CaptureWindow（Control.Handle）来捕获特定的控制：

The Utilities class. Call Utilities.CaptureWindow(Control.Handle) to capture a specific control:

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;
    }
}

该GDI32类：

The Gdi32 class:

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);
}

在USER32类：

The User32 class:

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);
}

中的常量使用：

The constants used:

    public const int SRCCOPY = 13369376;

的结构中使用：

The structs used:

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

一个友好的控制扩展方法：

A friendly Control extension method:

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

这是从我的 CC.Utilities 项目code片段，我专门写了它采取从截图WebBrowser控件。

This is a code snippet from my CC.Utilities project and I specifically wrote it to take screenshots from the WebBrowser control.

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