如何在VB.net中将PrintDocument（e.Graphic）另存为PDF

Question

我真的是 VB 新手。所以我有一个简单的程序，只有 4 个按钮（预览、打印、设置、保存）。这 4 个按钮用于打印、预览和保存简单的图形。问题是当我调用 PrintDocument1.print() 时，它不会将我重定向到保存文件或打印机选择。

这是我的代码：

Imports System.Drawing.Printing     
Public Class Form1

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    PrintPreviewDialog1.Document = PrintDocument1
    PrintPreviewDialog1.ShowDialog()
End Sub

Private Sub PrintDocument1_PrintPage_1(sender As Object, e As PrintPageEventArgs) Handles PrintDocument1.PrintPage
    Dim font As New Font("Arial", 16, FontStyle.Regular)
    e.Graphics.DrawString("Hello World", font, Brushes.Black, 200, 200)

End Sub

Private Sub btnPrint_Click(sender As Object, e As EventArgs) Handles btnPrint.Click
    PrintDialog1.Document = PrintDocument1
    If PrintDialog1.ShowDialog = Windows.Forms.DialogResult.OK Then
        PrintDocument1.Print()
    End If
End Sub

Private Sub btnPreview_Click(sender As Object, e As EventArgs) Handles btnPreview.Click
    PrintPreviewDialog1.Document = PrintDocument1
    PrintPreviewDialog1.ShowDialog()
End Sub

Private Sub btnSetting_Click(sender As Object, e As EventArgs) Handles Button3.Click
    PageSetupDialog1.Document = PrintDocument1
    PageSetupDialog1.Document.DefaultPageSettings.Color = False
    PageSetupDialog1.ShowDialog()
End Sub

Private Sub btnSave_Click(sender As Object, e As EventArgs) Handles btnSave.Click

End Sub
End Class

我想将我的 PrintDocument（包括 e.graphic.drawstring）保存到 Fialog 本地的 PDF 文件中以选择文件路径。

谢谢大家，恳请您的帮助。

Answer 1

您可以创建一个 pdfPrintDocument 类来代替 PrintDocument。 为我们要在其上绘制图形的每个页面创建一个位图图像。使用 iTextSharp 库，将图像转换为 pdf。使用示例是这里

Imports System.Drawing.Printing
Imports System.IO
Imports System.Data
Imports iTextSharp
Imports iTextSharp.text.pdf

Public Class pdfPrintDocument
    Inherits PrintDocument

    Public Shadows Event PrintPage(ByVal sender As System.Object, ByVal e As PrintPageEventArgs)
    Public Shadows Event BeginPrint As PrintEventHandler
    Public Shadows Event EndPrint As PrintEventHandler
    Public Shadows Sub print()
        Dim peArg As New PrintEventArgs
        RaiseEvent BeginPrint(Nothing, peArg)
        Dim pe As PrintPageEventArgs
        Dim fn As String = Me.DocumentName & ".pdf" 'Pdf file name
        fn = "x.pdf"
        'msgbox(fn)
        Using stream As New FileStream(fn, FileMode.Create) 'Create and open pdf file
            Dim img As iTextSharp.text.Image
            Dim pdfDoc As New iTextSharp.text.Document(iTextSharp.text.PageSize.A4, 0, 0, 0, 0)
            'pdfDoc.LeftMargin = 0
            PdfWriter.GetInstance(pdfDoc, stream)
            pdfDoc.Open()
            'msgbox(pdfdoc.PageSize.ToString)
            Do 'Keep generating images and add as pdfpage until HasmorePages is false
                Dim ps As PrinterSettings = Me.PrinterSettings
                Dim Psize as New Point(pdfDoc.PageSize.Width*1.38889, pdfDoc.PageSize.Height*1.38889) 'ItextSharp page size is in points. Multiply by 1.38889 to get in Pixels
                Dim im As Image = New Bitmap(psize.X, psize.Y) 'create image with size as page
                Dim g As Graphics = Graphics.FromImage(im) 'get graphics from image
                g.Clear(Color.White) 'Set page background
                Dim mb As Rectangle = ps.DefaultPageSettings.Bounds
                pe = New PrintPageEventArgs(g, New Rectangle(new Point(0, 0), psize), mb, Nothing) 'Create a print event with graphics for drawing
                pe.HasMorePages = False
                RaiseEvent PrintPage(Nothing, pe)
                
                img = iTextSharp.text.Image.GetInstance(im, system.Drawing.Imaging.ImageFormat.png)  'Convert image to pdfImage
                'img.ScalePercent(100) 
                img.ScaleToFit(pdfDoc.PageSize.Width, pdfDoc.PageSize.Height)  'Scale image to fit on pdfPage
                pdfDoc.Add(img) 'Add image to pdf document
                pdfDoc.NewPage()  'Create a new pdfPage
            Loop While pe.HasMorePages = True
            pdfDoc.Close()
            stream.Close()
        End Using        
        RaiseEvent EndPrint(Nothing, peArg)        
    End Sub
End Class

使用表单中的代码。

Imports System.Drawing.Printing

Public Class Form1
    Dim page As Int16 = 1
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim pd As New pdfPrintDocument  
        pd.DocumentName = "test"
        AddHandler pd.PrintPage, AddressOf PrintDocument1_PrintPage
        pd.Print()
    End Sub

    Private Sub PrintDocument1_PrintPage(ByVal sender As System.Object, ByVal e As System.Drawing.Printing.PrintPageEventArgs)
        Dim g As Graphics = e.Graphics
        g.DrawString("TEST Page " & page, New Font("Arial", 50), Brushes.Black, 20, 20)

        If page > 10 Then
            e.HasMorePages = False
            page = 1
            Exit Sub
        End If
        e.HasMorePages = True
        page += 1
    End Sub
End Class