禁用“文档查看器”中的“打印”按钮

Question

我想禁用相关按钮。

我的代码是：

<DocumentViewer x:Name="viewerDocument" 
                Document="{Binding GeneratedDocument}" />

预览如下

Answer 1

您必须重写默认模板（DocumentViewer ControlTemplate 示例）或子类

DocumentViewer

才能重写

DocumentViewerBase.OnPrintCommand

方法并调用

DocumentViewerBase.CancelPrint

方法。您还可以在可视化树中找到打印按钮并将

UIElement.IsEnabled

设置为

false

。

以下示例展示了如何禁用打印按钮：

MainWindow.xaml

<DocumentViewer Loaded="OnDocumentViewerLoaded" />

MainWindow.xaml.cs

private void OnDocumentViewerLoaded(object sender, RoutedEventArgs e)
{
  var documentViewer = (DocumentViewer)sender;
  Button printButton = documentViewer
    .EnumerateVisualChildElements<Button>()
    .First(button => button.Command == ApplicationCommands.Print);

  // Disable the print button
  printButton.IsEnabled = false;
}

private static IEnumerable<TChildren> EnumerateVisualChildElements<TChildren>(DependencyObject parent) where TChildren : DependencyObject
{
  for (int childIndex = 0; childIndex < VisualTreeHelper.GetChildrenCount(parent); childIndex++)
  {
    DependencyObject childElement = VisualTreeHelper.GetChild(parent, childIndex);
    if (childElement is Popup popup)
    {
      childElement = popup.Child;
    }

    if (childElement is TChildren child)
    {
      yield return child;
    }

    foreach (TChildren item in childElement.EnumerateVisualChildElements<TChildren>())
    {
      yield return item;
    }
  }
}