打印 WPF FlowDocument [英] Printing a WPF FlowDocument

问题描述

我正在用 WPF 构建一个演示应用程序，这对我来说是新的.我目前正在 FlowDocument 中显示文本，需要打印.

I'm building a demo app in WPF, which is new to me. I'm currently displaying text in a FlowDocument, and need to print it.

我使用的代码如下所示:

The code I'm using looks like this:

        PrintDialog pd = new PrintDialog();
        fd.PageHeight = pd.PrintableAreaHeight;
        fd.PageWidth = pd.PrintableAreaWidth;
        fd.PagePadding = new Thickness(50);
        fd.ColumnGap = 0;
        fd.ColumnWidth = pd.PrintableAreaWidth;

        IDocumentPaginatorSource dps = fd;
        pd.PrintDocument(dps.DocumentPaginator, "flow doc");

fd 是我的 FlowDocument，现在我使用默认打印机而不是允许用户指定打印选项.它工作正常，除了文档打印后，屏幕上显示的 FlowDocument 已更改为使用我指定的打印设置.

fd is my FlowDocument, and for now I'm using the default printer instead of allowing the user to specify print options. It works OK, except that after the document prints, the FlowDocument displayed on screen has changed to to use the settings I specified for printing.

我可以通过在打印后手动重置所有内容来解决此问题，但这是最好的方法吗?在打印 FlowDocument 之前，我应该制作它的副本吗?或者我应该考虑另一种方法吗?

I can fix this by manually resetting everything after I print, but is this the best way? Should I make a copy of the FlowDocument before I print it? Or is there another approach I should consider?

推荐答案

是的，在打印 FlowDocument 之前制作它的副本.这是因为分页和边距会不同.这对我有用.

yes, make a copy of the FlowDocument before printing it. This is because the pagination and margins will be different. This works for me.

    private void DoThePrint(System.Windows.Documents.FlowDocument document)
    {
        // Clone the source document's content into a new FlowDocument.
        // This is because the pagination for the printer needs to be
        // done differently than the pagination for the displayed page.
        // We print the copy, rather that the original FlowDocument.
        System.IO.MemoryStream s = new System.IO.MemoryStream();
        TextRange source = new TextRange(document.ContentStart, document.ContentEnd);
        source.Save(s, DataFormats.Xaml);
        FlowDocument copy = new FlowDocument();
        TextRange dest = new TextRange(copy.ContentStart, copy.ContentEnd);
        dest.Load(s, DataFormats.Xaml);

        // Create a XpsDocumentWriter object, implicitly opening a Windows common print dialog,
        // and allowing the user to select a printer.

        // get information about the dimensions of the seleted printer+media.
        System.Printing.PrintDocumentImageableArea ia = null;
        System.Windows.Xps.XpsDocumentWriter docWriter = System.Printing.PrintQueue.CreateXpsDocumentWriter(ref ia);

        if (docWriter != null && ia != null)
        {
            DocumentPaginator paginator = ((IDocumentPaginatorSource)copy).DocumentPaginator;

            // Change the PageSize and PagePadding for the document to match the CanvasSize for the printer device.
            paginator.PageSize = new Size(ia.MediaSizeWidth, ia.MediaSizeHeight);
            Thickness t = new Thickness(72);  // copy.PagePadding;
            copy.PagePadding = new Thickness(
                             Math.Max(ia.OriginWidth, t.Left),
                               Math.Max(ia.OriginHeight, t.Top),
                               Math.Max(ia.MediaSizeWidth - (ia.OriginWidth + ia.ExtentWidth), t.Right),
                               Math.Max(ia.MediaSizeHeight - (ia.OriginHeight + ia.ExtentHeight), t.Bottom));

            copy.ColumnWidth = double.PositiveInfinity;
            //copy.PageWidth = 528; // allow the page to be the natural with of the output device

            // Send content to the printer.
            docWriter.Write(paginator);
        }

    }

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