使用C＃，WPF和DWM保存窗口的屏幕截图

这是对这个问题的后续问题

上述解决方案使用DWM显示活动窗口的缩略图。 如果我理解正确，它的工作原理是让你指定要查看的应用程序的窗口句柄，然后让你提供一个窗口句柄和窗口上应该绘制目标窗口内容的位置。

有没有办法将窗口屏幕直接渲染到BitmapImage或Image而不是直接在窗口中的某个位置绘制？ （基本上只是抓住窗口的屏幕截图 – 即使它被另一个窗口覆盖 – 没有使用更新缩略图。）

谢谢你的帮助！

Answer 1

Control.DrawToBitmap并不总是有效，所以我使用了以下本机API调用来提供更一致的结果：

公用事业类。 调用Utilities.CaptureWindow（Control.Handle）来捕获特定控件：

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); } 

使用的常数：

  public const int SRCCOPY = 13369376; 

结构使用：

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

友好的控制扩展方法：

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

Answer 2

使用Control.DrawToBitmap方法

 Image img = myForm.DrawToBitmap(); Image img = myPanel.DrawToBitmap();