Question

回答这个问题......

Printing page x of y in .Net

接受的答案包括这一陈述......

您不必打印两次，只需模拟打印即可第一次。

那么，如何在没有任何输出到打印机或屏幕的情况下首次通过文档？

Answer 1

您需要创建一个打印机设备上下文，并使用该设备上下文作为参考DC渲染您的页面，同时跟踪您渲染的页面数。这必须在.NET Printing infrastructure的范围之外完成。

获取参考打印机DC
基于参考打印机DC创建位图
创建要在位图上绘制的图形对象
使用图形对象（此处计数页面）将页面渲染为位图
要打印的更多数据？转到4

以下是第1步的镜头，假设您正在使用winforms ......

 Private Function GetHighResolutionGraphics() As Graphics

        Try

            Dim HighestResolution As Printing.PrinterResolution = Nothing
            Dim HighestResolutionPrinter As String = ""
            Dim XResolution As Integer = Integer.MinValue

            Using dlg As New PrintDialog

                For Each Printer As String In Printing.PrinterSettings.InstalledPrinters
                    dlg.PrinterSettings.PrinterName = Printer
                    For Each Resolution As Printing.PrinterResolution In dlg.PrinterSettings.PrinterResolutions
                        Using gr As Graphics = dlg.PrinterSettings.CreateMeasurementGraphics()
                            If gr.DpiX > XResolution Then
                                HighestResolution = Resolution
                                HighestResolutionPrinter = Printer
                                XResolution = gr.DpiX
                            End If
                        End Using
                    Next
                Next

                dlg.PrinterSettings.PrinterName = HighestResolutionPrinter
                dlg.PrinterSettings.DefaultPageSettings.PrinterResolution = HighestResolution

                Return dlg.PrinterSettings.CreateMeasurementGraphics()

            End Using

        Catch ex As Exception
            ' handle or ignore .NET AccessViolation for certain network printers that are turned off, etc...
        End Try

        Return Me.CreateGraphics()

    End Function

第2步“简单地”使用返回的参考图形对象和已经实现的PagePrint事件代码将页面渲染到适当的位图，同时跟踪您正在渲染的页面数。不要忘记将PagePrint事件重构为接受Graphics对象的单独例程，以便它可用于打印，预览和页码。不要忘记处理Graphics对象和Bitmap

using gfxReference as Graphics = GetHighResolutionGraphics()
  using bmpPage as new Bitmap(gfxReference.DpiX * 8.5, gfxReference.DpiY * 11)
    using gfxRender as Graphics = Graphics.FromImage(bmpPage)
      gfxRender.Clear(Color.White)
      // Existing PagePrint event logic goes here (uses gfxRender)
      // Track Number of pages printed
    end using
  end using
end using

如何预处理PrintDocument以计算打印前的总页数？

1 个答案: