Printing a WPF FlowDocument

Question

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.

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 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.

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?

question from:https://stackoverflow.com/questions/345009/printing-a-wpf-flowdocument

Answer 1

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);
        }

    }