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使用PrintDialog 打印Grid

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        private void btnPrint_Click(object sender, RoutedEventArgs e)
        {
            PrintDialog dialog = new PrintDialog();  
            if (dialog.ShowDialog() == true)
            {
                dialog.UserPageRangeEnabled = true; 
                dialog.PrintVisual(Grid_Main,  DateTime.Now.ToString("yyyy-MM-dd") );
            }
        }

使用 printDialog 的 printVisual方法发硬 Grid (Grid_main是Grid的名称) 当数据量很大时一页纸不够打印，但打印机只打印一张纸，完了以后就不打印了。怎么实现可以打印多页？

已编辑 ______卡托丶 2016年1月2日 8:42

2016年1月2日 8:41

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您好卡托，

>>怎么实现可以打印多页？

PrintVisual方法并不会自动帮助我们把打印结果分为多页。我们需要手动去实现。我们可以通过在一个FixedDocument中添加多个FixedPage来实现，最后调用PrintDialog的PrintDocument方法来打印这个多页的文档。这其中一个难点是如果分析一个WPF的控件并把它动态的拆分成为多个页面并放入不同的FixedPage中。下面一个Command实现了这个功能，供您参考。

public class PrintCommand : ICommand
{
    public bool CanExecute(object parameter)
    {
        return true;
    }

    public void Execute(object parameter)
    {
        if (parameter is FrameworkElement)
        {
            FrameworkElement objectToPrint = parameter as FrameworkElement;
            PrintDialog printDialog = new PrintDialog();
            if ((bool)printDialog.ShowDialog().GetValueOrDefault())
            {
                Mouse.OverrideCursor = Cursors.Wait;
                System.Printing.PrintCapabilities capabilities =
                  printDialog.PrintQueue.GetPrintCapabilities(printDialog.PrintTicket);
                double dpiScale = 300.0 / 96.0;
                FixedDocument document = new FixedDocument();
                try
                {
                    // 修改此UI Control的外观来适应打印页的宽度
                    objectToPrint.Width = capabilities.PageImageableArea.ExtentWidth;
                    objectToPrint.UpdateLayout();
                    objectToPrint.Measure(new Size(double.PositiveInfinity, double.PositiveInfinity));
                    Size size = new Size(capabilities.PageImageableArea.ExtentWidth,
                                         objectToPrint.DesiredSize.Height);
                    objectToPrint.Measure(size);
                    size = new Size(capabilities.PageImageableArea.ExtentWidth,
                                    objectToPrint.DesiredSize.Height);
                    objectToPrint.Measure(size);
                    objectToPrint.Arrange(new Rect(size));

                    //将这个UI控件转换为一个bitmap
                    double dpiX = 300;
                    double dpiY = 300;
                    RenderTargetBitmap bmp = new RenderTargetBitmap(Convert.ToInt32(
                      capabilities.PageImageableArea.ExtentWidth * dpiScale),
                      Convert.ToInt32(objectToPrint.ActualHeight * dpiScale),
                      dpiX, dpiY, PixelFormats.Pbgra32);
                    bmp.Render(objectToPrint);

                    //将RenderTargetBitmap转换为bitmap
                    PngBitmapEncoder png = new PngBitmapEncoder();
                    png.Frames.Add(BitmapFrame.Create(bmp));
                    System.Drawing.Bitmap bmp2;
                    using (MemoryStream memoryStream = new MemoryStream())
                    {
                        png.Save(memoryStream);
                        bmp2 = new System.Drawing.Bitmap(memoryStream);
                    }
                    document.DocumentPaginator.PageSize =
                      new Size(printDialog.PrintableAreaWidth, printDialog.PrintableAreaHeight);

                    //将bitmap拆分为多个Page
                    int pageBreak = 0;
                    int previousPageBreak = 0;
                    int pageHeight =
                        Convert.ToInt32(capabilities.PageImageableArea.ExtentHeight * dpiScale);
                    while (pageBreak < bmp2.Height - pageHeight)
                    {
                        pageBreak += pageHeight; 

                        while (!IsRowGoodBreakingPoint(bmp2, pageBreak))
                            pageBreak--;

                        PageContent pageContent = generatePageContent(bmp2, previousPageBreak,
                          pageBreak, document.DocumentPaginator.PageSize.Width,
                          document.DocumentPaginator.PageSize.Height, capabilities);
                        document.Pages.Add(pageContent);
                        previousPageBreak = pageBreak;
                    }

                    //最后一页
                    PageContent lastPageContent = generatePageContent(bmp2, previousPageBreak,
                      bmp2.Height, document.DocumentPaginator.PageSize.Width,
                      document.DocumentPaginator.PageSize.Height, capabilities);
                    document.Pages.Add(lastPageContent);
                }
                finally
                {
                    objectToPrint.Width = double.NaN;
                    objectToPrint.UpdateLayout();
                    objectToPrint.LayoutTransform = new ScaleTransform(1, 1);
                    Size size = new Size(capabilities.PageImageableArea.ExtentWidth,
                                         capabilities.PageImageableArea.ExtentHeight);
                    objectToPrint.Measure(size);
                    objectToPrint.Arrange(new Rect(new Point(capabilities.PageImageableArea.OriginWidth,
                                          capabilities.PageImageableArea.OriginHeight), size));
                    Mouse.OverrideCursor = null;
                }
                printDialog.PrintDocument(document.DocumentPaginator, "Print Document Name");
            }
        }
    }

    private PageContent generatePageContent(System.Drawing.Bitmap bmp, int top,
     int bottom, double pageWidth, double PageHeight,
     System.Printing.PrintCapabilities capabilities)
    {
        FixedPage printDocumentPage = new FixedPage();
        printDocumentPage.Width = pageWidth;
        printDocumentPage.Height = PageHeight;

        int newImageHeight = bottom - top;
        System.Drawing.Bitmap bmpPage = bmp.Clone(new System.Drawing.Rectangle(0, top,
               bmp.Width, newImageHeight), System.Drawing.Imaging.PixelFormat.Format32bppArgb);

        Image pageImage = new Image();
        BitmapSource bmpSource =
            System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap(
                bmpPage.GetHbitmap(),
                IntPtr.Zero,
                System.Windows.Int32Rect.Empty,
                BitmapSizeOptions.FromWidthAndHeight(bmp.Width, newImageHeight));

        pageImage.Source = bmpSource;
        pageImage.VerticalAlignment = VerticalAlignment.Top;

        printDocumentPage.Children.Add(pageImage);

        PageContent pageContent = new PageContent();
        ((System.Windows.Markup.IAddChild)pageContent).AddChild(printDocumentPage);

        FixedPage.SetLeft(pageImage, capabilities.PageImageableArea.OriginWidth);
        FixedPage.SetTop(pageImage, capabilities.PageImageableArea.OriginHeight);

        pageImage.Width = capabilities.PageImageableArea.ExtentWidth;
        pageImage.Height = capabilities.PageImageableArea.ExtentHeight;
        return pageContent;
    }

    private bool IsRowGoodBreakingPoint(System.Drawing.Bitmap bmp, int row)
    {
        double maxDeviationForEmptyLine = 1627500;
        bool goodBreakingPoint = false;

        if (rowPixelDeviation(bmp, row) < maxDeviationForEmptyLine)
            goodBreakingPoint = true;

        return goodBreakingPoint;
    }


    private double rowPixelDeviation(System.Drawing.Bitmap bmp, int row)
    {
        int count = 0;
        double total = 0;
        double totalVariance = 0;
        double standardDeviation = 0;
        System.Drawing.Imaging.BitmapData bmpData = bmp.LockBits(new System.Drawing.Rectangle(0, 0, 
               bmp.Width, bmp.Height), System.Drawing.Imaging.ImageLockMode.ReadOnly, bmp.PixelFormat);
        int stride = bmpData.Stride;
        IntPtr firstPixelInImage = bmpData.Scan0;

        unsafe
        {
            byte* p = (byte*)(void*)firstPixelInImage;
            p += stride * row;  // find starting pixel of the specified row
            for (int column = 0; column < bmp.Width; column++)
            {
                count++;  //count the pixels

                byte blue = p[0];
                byte green = p[1];
                byte red = p[3];

                int pixelValue = System.Drawing.Color.FromArgb(0, red, green, blue).ToArgb();
                total += pixelValue;
                double average = total / count;
                totalVariance += Math.Pow(pixelValue - average, 2);
                standardDeviation = Math.Sqrt(totalVariance / count);

                // go to next pixel
                p += 3;
            }
        }
        bmp.UnlockBits(bmpData);

        return standardDeviation;
    }

    public event EventHandler CanExecuteChanged;
}

我们只需要在项目中创建一个PrintCommand类，然后把上面的代码都拷贝进去，最后执行以下代码即可分多页打印我们的Grid。

PrintCommand pc = new PrintCommand();
pc.Execute(Grid_Main);

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已建议为答案 Xavier Xie-MSFTModerator 2016年1月21日 3:22
已标记为答案 Xavier Xie-MSFTModerator 2016年1月23日 5:43
已编辑 Xavier Xie-MSFTModerator 2016年2月4日 2:04 编辑

2016年1月5日 2:28

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使用PrintDialog 打印Grid

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