Question

所以我正在构建一个WPF拖放设计器。

一旦用户完成设计，我希望他们能够打印出他们拥有的东西。

这一直有效，直到我决定我画布上的所有项目实际上都应该数据绑定到视图模型。为此，我将画布包装在Items Control中。我现在遇到的问题是我构建的打印功能无法访问画布来打印它。我愿意接受建议。

<ItemsControl x:Name="CanvasItemsControl" Grid.Column="1" Width="600" Height="800"  ItemsSource="{Binding CanvasElements}">
    <ItemsControl.ItemsPanel>
       <ItemsPanelTemplate>
           <Canvas Grid.Column="1" AllowDrop="True" Width="600" Height="800" 
                  x:Name="CanvasControl"                
                  Background="White"  
                  DragEnter="CanvasFlowDocument_DragEnter" 
                  DragLeave="CanvasFlowDocument_DragLeave" 
                  DragOver="CanvasFlowDocument_DragOver" 
                  Drop="CanvasFlowDocument_Drop"/>
      </ItemsPanelTemplate>
   </ItemsControl.ItemsPanel>
   <ItemsControl.ItemTemplate>
           <DataTemplate>
              <controls:CanvasElement />
           </DataTemplate>
   </ItemsControl.ItemTemplate>
</ItemsControl>

C＃

 private void PrintCanvas()
 {

   PrintDialog pd = new PrintDialog();

   if (pd.ShowDialog() == true)
   {

     /*

      NEED TO ACCESS CANVAS CONTROL HERE TO PRINT

      I KNOW THE BELOW PRINT METHOD WORKS. 

      IT WORKED UNTIL I ADDED THE ITEMS CONTROL WRAPPER AROUND THE CANVAS                

     */


      //get the size of the printer page 
      PrintCapabilities capabilities = pd.PrintQueue.GetPrintCapabilities(pd.PrintTicket);

      double pageMargin = Math.Min(capabilities.PageImageableArea.OriginWidth, capabilities.PageImageableArea.OriginHeight);

      double additionalMargin = Math.Max(0, 20 - pageMargin);
      Size pageSize = new Size(capabilities.PageImageableArea.ExtentWidth - additionalMargin * 2, capabilities.PageImageableArea.ExtentHeight - additionalMargin * 2);

      //get scale of the print wrt to screen of WPF visual 
      double scale = Math.Min(pageSize.Width / CanvasControl.ActualWidth, pageSize.Height / CanvasControl.ActualHeight);
      Size printSize = new Size(CanvasControl.ActualWidth * scale, CanvasControl.ActualHeight * scale);

      Point upperLeft = new Point(capabilities.PageImageableArea.OriginWidth + additionalMargin, capabilities.PageImageableArea.OriginHeight + additionalMargin);

      //Transform the Visual to scale 
      CanvasControl.LayoutTransform = new ScaleTransform(scale, scale);
      CanvasControl.Measure(printSize);
      CanvasControl.Arrange(new Rect(upperLeft, printSize));


      FlowDocument CanvasFlowDocument = new FlowDocument();
      BlockUIContainer buiCont = new BlockUIContainer();


      CanvasControl.Drop -= CanvasFlowDocument_Drop;
      CanvasControl.DragOver -= CanvasFlowDocument_DragOver;
      CanvasControl.DragLeave -= CanvasFlowDocument_DragLeave;
      CanvasControl.DragLeave -= CanvasFlowDocument_DragEnter;


      Grid parent = (Grid)CanvasControl.Parent;

      parent.Children.Remove(CanvasControl);

      buiCont.Child = CanvasControl;
      CanvasFlowDocument.Blocks.Add(buiCont);

      pd.PrintDocument((CanvasFlowDocument as IDocumentPaginatorSource).DocumentPaginator, "Template");

      CanvasFlowDocument.Blocks.Clear();
      buiCont.Child = null;

      ReloadUI(parent);
   }
}

Answer 1

您应该可以使用PrintDialog.PrintVisual(Visual,string)直接打印出您的控件。您可能需要使用大小，但是您必须执行调整大小的代码才能正常工作。请参阅this post，该this article类似，并链接到{{3}}作为可能的解决方案。

从Items Control获取ItemsPanel

1 个答案: