c# - WPF 打印/xps 问题

Question

我编写了以下代码块，当发送到物理打印机时可以完美地打印我的 ListBox，但是当尝试将它发送到 XPS 打印机驱动程序或使用 XpsDocumentWriter 类时(我假设它们在hood) 我收到以下异常:

System.ArgumentException 未被用户代码处理 Message=Width 和 Height 必须是非负数。 来源=ReachFramework 堆栈跟踪: 在 System.Windows.Xps.Serialization.VisualSerializer.WriteTileBrush(字符串元素、TileBrush 画笔、矩形边界)

异常显然指向一个没有正确宽度/高度的项目，但是我在将它发送到不同打印机(物理和 XPS 驱动程序)时调试了代码，但我没有发现任何差异。

下面是我如何创建视觉效果以发送到打印机:

private ScrollViewer GeneratePrintableView()
    {
        ScrollViewer scrollView = new ScrollViewer();

        Grid grid = new Grid { Background = Brushes.White, Width = this.myListBox.ActualWidth, Height = this.myListBox.ActualHeight };

        grid.RowDefinitions.Add(new RowDefinition());
        grid.RowDefinitions[0].Height = new GridLength(0, GridUnitType.Auto);
        grid.RowDefinitions.Add(new RowDefinition());
        grid.RowDefinitions[1].Height = new GridLength(0, GridUnitType.Auto);

        // Add the title and icon to the top
        VisualBrush titleClone = new VisualBrush(this.TitleBar);
        var titleRectangle = new Rectangle { Fill = titleClone, Width = this.TitleBar.ActualWidth, Height = this.TitleBar.ActualHeight };
        grid.Children.Add(titleRectangle);
        Grid.SetRow(titleRectangle, 0);

        this.myListBox.Width = this.myListBox.ActualWidth;
        this.myListBox.Height = this.myListBox.ActualHeight;

        VisualBrush clone = new VisualBrush(this.myListBox) { Stretch = Stretch.None, AutoLayoutContent = true };
        var rectangle = new Rectangle { Fill = clone, Width = this.myListBox.ActualWidth, Height = this.myListBox.ActualHeight };
        Border border = new Border { Background = Brushes.White, Width = this.myListBox.ActualWidth, Height = this.myListBox.ActualHeight };
        border.Child = rectangle;
        grid.Children.Add(border);
        Grid.SetRow(border, 1);

        scrollView.Width = this.myListBox.ActualWidth;
        scrollView.Height = this.myListBox.ActualHeight;
        scrollView.Content = grid;
        scrollView.VerticalScrollBarVisibility = ScrollBarVisibility.Hidden;

        return scrollView;
    }

这是我的 DocumentPaginator 实现中的 GetPage 覆盖:

public override DocumentPage GetPage(int pageNumber)
    {
        Page page = new Page();
        double z = 0.0;

        this.grid = new Grid();
        this.grid.RowDefinitions.Add(new RowDefinition());
        this.grid.RowDefinitions[0].Height = new GridLength(0, GridUnitType.Auto);

        this.grid.Children.Add(this.printViewer);
        Grid.SetRow(this.printViewer, 0);

        //Adjusting the vertical scroll offset depending on the page number
        if (pageNumber + 1 == 1) //if First Page
        {
            this.printViewer.ScrollToVerticalOffset(0);
            this.printViewer.UpdateLayout();
        }
        else if (pageNumber + 1 == _verticalPageCount) //if Last Page
        {
            if (this.printViewer.ScrollableHeight == 0) //If printing only single page and the contents fits only on one page
            {
                this.printViewer.ScrollToVerticalOffset(0);
                this.printViewer.UpdateLayout();

            }
            else if (this.printViewer.ScrollableHeight <= this.printViewer.Height) //If scrollconentheight is less or equal than scrollheight
            {
                this.printViewer.Height = this.printViewer.ScrollableHeight;
                this.printViewer.ScrollToEnd();
                this.printViewer.UpdateLayout();
            }
            else //if the scrollcontentheight is greater than scrollheight then set the scrollviewer height to be the remainder between scrollcontentheight and scrollheight
            {
                this.printViewer.Height = (this.printViewer.ScrollableHeight % this.printViewer.Height) + 5;
                this.printViewer.ScrollToEnd();
                this.printViewer.UpdateLayout();
            }
        }
        else //Other Pages
        {
            z = z + this.printViewer.Height;
            this.printViewer.ScrollToVerticalOffset(z);
            this.printViewer.UpdateLayout();
        }

        page.Content = this.grid; //put the grid into the page
        page.Arrange(new Rect(this.originalMargin.Left, this.originalMargin.Top, this.ContentSize.Width, this.ContentSize.Height));
        page.UpdateLayout();

        return new DocumentPage(page);
    }

有趣的是，如果我将矩形的填充更改为画笔而不是克隆，那么我不会收到异常并且输出的文件大小正确。

我花了一天多的时间试图调试为什么这不起作用，我希望外面有人看到过类似的问题或者能够指出我犯的任何错误。

感谢您的任何回复。

Answer 1

我不得不放弃寻找 VisualBrush 的解决方案。如果画笔的 Visual 中有一个 GroupBox，我永远无法让它生成 XPS 文件。它总是以

失败

System.ArgumentException 未被用户代码处理 Message=Width and Height 必须是非负数。 Source=ReachFramework StackTrace:在 System.Windows.Xps.Serialization.VisualSerializer.WriteTileBrush(字符串元素，TileBrush 画笔，矩形边界)

解决方法是克隆应该放在 VisualBrush (Is there an easy/built-in way to get an exact copy (clone) of a XAML element?) 中的内容并直接在 Grid 而不是 VisualBrush 中使用它