我正在尝试捕获WebBrowser控件的内容。DrawToBitmap()可以完美地工作,但是WebBrowser控件的文档中不支持它。我一直在尝试寻找另一种捕获WebBrowser控件的内容并将其保存到本地图像文件的方法。
DrawToBitmap()
是否有人有任何变通办法或其他方法将WebBrowser控件的内容保存到本地图像文件?
Control.DrawToBitmap并不总是能正常工作,因此我诉诸于以下提供更一致结果的本机API调用:
实用程序类。调用Utilities.CaptureWindow(Control.Handle)捕获特定的控件:
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Control扩展方法:
public static class ControlExtensions { public static Image DrawToImage(this Control control) { return Utilities.CaptureWindow(control.Handle); } }
这是我CC.Utilities项目的代码段,我专门编写了该代码段以从WebBrowser控件中截取屏幕截图。