Question

我想要捕获屏幕的图像，但是我的应用程序中有一些wpf控件我不想出现在屏幕截图中。使用下面的代码，隐藏的控件有时仍会出现在屏幕截图中。我如何确保不会发生这种情况？

Window window = new Window();
Button button = new Button();

void ShowWindow()
{
    button.Content = "button";
    button.ToolTip = "tooltip";
    window.Content = button;
    window.Show();

    button.Click += new RoutedEventHandler(button_Click);
}

void button_Click(object sender, RoutedEventArgs e)
{
    //Hide some controls and all tooltips in the window
    ToolTipService.SetIsEnabled(window, false);
    button.Visibility = Visibility.Hidden;

    //Block until wpf renders
    Application.Current.Dispatcher.Invoke(
        System.Windows.Threading.DispatcherPriority.Background, 
        new System.Threading.ThreadStart(delegate { }));

    //Take screenshot
    Bitmap bmpScreenshot = new Bitmap(System.Windows.Forms.Screen.PrimaryScreen.Bounds.Width,
                               System.Windows.Forms.Screen.PrimaryScreen.Bounds.Height,
                               System.Drawing.Imaging.PixelFormat.Format32bppArgb);
    Graphics gfxScreenshot = Graphics.FromImage(bmpScreenshot);
    gfxScreenshot.CopyFromScreen(System.Windows.Forms.Screen.PrimaryScreen.Bounds.X,
                                System.Windows.Forms.Screen.PrimaryScreen.Bounds.Y,
                                0, 0,
                                System.Windows.Forms.Screen.PrimaryScreen.Bounds.Size,
                                CopyPixelOperation.SourceCopy);
    bmpScreenshot.Save("Screenshot.png", ImageFormat.Png);

    //Restore controls and tooltips
    button.Visibility = Visibility.Visible;
    ToolTipService.SetIsEnabled(window, true);
}

Answer 1

尝试在调度程序上使用低优先级，但仍然不能保证（source）。

另外，根据我的理解，WPF在UI线程空闲（或长时间阻塞）之前不会启动渲染过程，因此您可能希望将调度阻塞和放置。实际后台线程中的快照代码（或让调度程序异步调用快照代码）。然后在快照线程完成后恢复按钮可见性。

Answer 2

您是否尝试过将DispatcherPriority设为Normal而不是Background？

屏幕截图前更新

2 个答案: