從項目控制獲取ItemsPanel

Question

因此，我正在構建一個WPF拖放設計器。

一旦用戶完成設計，我希望他們能夠打印他們擁有的東西。

這是工作，直到我決定我的畫布上的所有項目應該實際上是數據綁定到視圖模型。爲此，我將我的畫布包裹在一個Items控件中。我現在遇到的問題是我構建的打印函數無法訪問畫布以進行打印。我樂於接受建議。

<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

你應該能夠使用PrintDialog.PrintVisual(Visual,string)直接打印出你的控制。儘管您可能需要使用大小，但您必須執行調整大小的代碼才能正常工作。請參閱this post，它與this article類似，並鏈接至可能的解決方案。