使用pdfsharp将多个图像转换为pdf

问题描述

我正在尝试使用 pdfsharp库将多个图像转换为pdf.

I am trying to convert multiple images to pdf using pdfsharp library.

我能够转换单个图像，并且效果很好.

I am able to convert single image and it works pretty well.

在将bulk images转换为single pdf时，我面临的问题是它将所有图像都进行转换，但是在转换后如果我检查它仅显示最后一个图像，因为它没有追加到现有图像上，覆盖上一张图片.

And while converting bulk images to single pdf I am facing problem that it takes all the images and converts them but after conversion If I check it shows me only the last image as it is not appending to the existing image and it overwrites the previous image.

那我该如何纠正呢?

我第一次使用pdf库并向我指出任何错误时将提供任何帮助，我将很高兴知道更多有关此的信息，但是如果您指出我没有任何帮助，我将不为所动我犯的错误.

Any help will be appreciated as I am first time working with pdf library and point me out If I am doing any mistake.And I will be gald to know more about this and I don't feel though If you pointed me out the mistake I have done.

这是我的代码:

 Private Sub btnAddFolder_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnAddFolder.Click
            If Me.FolderBrowserDialog1.ShowDialog = Windows.Forms.DialogResult.OK Then

            Dim f As New DirectoryInfo(Me.FolderBrowserDialog1.SelectedPath)
            Dim fso As New System.Object
            For Each file As FileInfo In f.GetFiles
                Select Case file.Extension.ToLower
                    Case ".jpg", ".bmp", ".gif", ".png"
                        Me.ThumbControl1.BackgroundImage = Nothing
                        Me.CheckedListBox1.Items.Add(file.FullName, CheckState.Checked)
                        Me.ThumbControl1.AddThumbnail(file.FullName)
                        Me.ThumbControl1.BackgroundImage = Nothing
                        Me.CheckedListBox1.SelectedIndex = 0
                End Select
            Next
            End If
    End Sub

后台工作者:

 Private Sub bw_DoWork(ByVal sender As Object, ByVal e As DoWorkEventArgs) Handles bw.DoWork
        For pix As Integer = 0 To CheckedListBox1.CheckedItems.Count - 1
            Try
                Dim source As String = CheckedListBox1.Items(pix).ToString()
                Dim destinaton As String = (TryCast(e.Argument, String()))(1)

                Dim doc As New PdfDocument()
                doc.Pages.Add(New PdfPage())
                Dim xgr As XGraphics = XGraphics.FromPdfPage(doc.Pages(0))
                Dim img As XImage = XImage.FromFile(source)

                xgr.DrawImage(img, 0, 0)
                doc.Save(destinaton)
                doc.Close()
                success = True
            Catch ex As Exception
                MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
            End Try
        Next
    End Sub

转换按钮:

  Private Sub btnConvert_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnConvert.Click
         bw.RunWorkerAsync(New String(1) {srcFile, destFile})
  End sub

保存Pdf:

Private Sub btnSelectDest_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnSelectDest.Click
        sfdDestFile.Filter = "PDF Files(*.pdf)|*.pdf"
        If sfdDestFile.ShowDialog() <> System.Windows.Forms.DialogResult.OK Then
            Return
        End If
        destFile = sfdDestFile.FileName
 End Sub

推荐答案

问题是您在循环中每次通过都会创建一个新的PDF文档.您需要将其移出循环.另外，您引用的是第0页，而不是第pix页.这是我的解决方法:

The problem is that you are creating a new PDF document on each pass through the loop. You need to move this outside the loop. Also, you are referencing page 0, not page pix. Here is how I would fix it:

Private Sub bw_DoWork(ByVal sender As Object, ByVal e As DoWorkEventArgs) Handles bw.DoWork
    Dim doc As New PdfDocument()

    For pix As Integer = 0 To CheckedListBox1.CheckedItems.Count - 1
        Try
            Dim source As String = CheckedListBox1.Items(pix).ToString()
            Dim oPage As New PDFPage()

            doc.Pages.Add(oPage)
            Dim xgr As XGraphics = XGraphics.FromPdfPage(oPage)
            Dim img As XImage = XImage.FromFile(source)

            xgr.DrawImage(img, 0, 0)
            success = True
        Catch ex As Exception
            MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
        End Try
    Next

    Dim destinaton As String = (TryCast(e.Argument, String()))(1)
    doc.Save(destinaton)
    doc.Close()
End Sub

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