如何以编程方式从 PrintDocument 打印特定页面？

Question

有没有办法以System.Drawing.Printing.PrintDocument编程方式仅打印选定的页面（例如第 3-5 页）？

我正在使用这段代码：

myPrintDocument.Print();

但这样我就无法以编程方式跳过页面。我考虑过显示PrintDialog 类的修改版本、跳过我不想要的页面、打印文档并以编程方式关闭 PrintDialog 窗口（以便它仅闪烁）的可能性。但这有点麻烦。

Answer 1

PrinterSettings您可以在事件中设置PrintDocument.BeginPrint。

您放置打印代码的事件PrintDocument.PrintPage将由打印控制器针对每一页引发，直到PrinterSettings. 例如，如果您有 10 页PrintDocument并且设置了PrintDocument.PrinterSettings.ToPage = 5，则打印控制器将为PrintPage每个页面引发该事件，直到处理第 5 页。

如果您要跳页，例如PrinterSettings.FromPage = 3跳至ToPage = 5，则打印控制器将引发PrintPage事件 3 次。PrintPage从 3 到 5（含），每计数一个事件。

打印控制器不决定事件打印什么内容PrintPage。它只会在范围内的每个计数页面引发一次事件。例如，如果您指定FromPage = 4to FromPage = 6，打印控制器将引发完全相同数量的PrintPage事件，并且它甚至不知道差异！它不知道该PrintPage事件正在打印哪一页。它只知道引发该PrintPage事件 3 次。

我的观点是，您的代码PrintPage必须处理所有跳过的页面，而不绘制任何内容。然后，该同一PrintPage事件中的代码必须处理并绘制要打印的“当前页面”，然后返回，以便打印控制器可以引发下一个PrintPage事件。

这是伪代码：

void Setup_Printing()
{
  myPrintDocument.BeginPrint += On_BeginPrint;
  myPrintDocument.PrintPage += On_PrintPage;
}

// Page Index variable
int indexCuurentPage = 0;

void On_BeginPrint(object sender, PrintEventArgs e)
{
  indexCuurentPage = 0;
  ((PrintDocument)sender).PrinterSettings.PrintRange = PrintRange.SomePages;
  ((PrintDocument)sender).PrinterSettings.FromPage = 3;
  ((PrintDocument)sender).PrinterSettings.ToPage = 5;
}


void On_PrintPage(object sender, PrintPageEventArgs ppea)
{
  // Set up a loop to process pages.
  bool bProcessingPages = true;
  while (bProcessingPages)
  {
    indexCurrentPage++;

    // Set isPageInRange flag to true if this indexCurrentPage is in the selected range of pages
    bool isPageInRange = (theCurrentPage >= ppea.PageSettings.PrinterSettings.FromPage);
    isPageInRange = isPageInRange && (theCurrentPage =< ppea.PageSettings.PrinterSettings.ToPage);

    if (isPageInRange)
    {
      // Process your data and print this page then exit the loop.  
      try
      {
        //// TO DO - Process Data ////
        //// TO DO - Draw Data to ppea.Graphics ////
        // Note:  Do not set the ppea.HasMorePages to true.  Let the Printer Controller do it.
      }
      catch
      {
        // Abort printing more pages if there was an error.
        ppea.HasMorePages = false;
      }
      // Set the loop exit flag.  We could use "return;" instead if we do not want to do more.
      bProcessingPages = false;
    }
    else
    {
      // Process your data and Do Not Draw on the ppea.Graphics.
      try
      {
        //// TO DO - Process Data ////
      }
      catch
      {
        // Abort printing more pages if there was an error.
        ppea.HasMorePages = false;
        // Set the loop exit flag.  We could use "return;" instead if we do not want to do more.
        bProcessingPages = false;
      }
      // Stay in the processing loop until you either need to actually Print a Page
      // or until you run out of data and pages to print.
    }

    // check to see if we ran out of pages to print
    if (indexCurrentPage >= ppea.PageSettings.PrinterSettings.ToPage)
    {
      // Done.  We do not need to set the HasMorePages = false
      bProcessingPages = false;
    }
  } // end while processing pages

  // The print controller will decide to raise the next PrintPage event if it needs to.
  // If You set the ppea.HasMorePages = false, then it will stop any more page events. 
  // If You set the ppea.HasMorePages = true, 
  //    then I'm not sure what the print controller will do if it ran out of pages!
}