主题：pdfsharp文件操作pdf，怎么实现目录下的pdf批量合并成一个呢？怎么实现给新生成的pdf添加水印？怎么实现给新生成的pdf从指定的页数后面开始添加数字作为编码？

Dim ymsum As Integer = 0

For Each File As String In FileSys.GetFiles("C:\Users\Administrator\Desktop") '遍历指定目录下的文件

    If FileSys.GetName(File).Contains(".pdf") Then '找到名称中含pdf的文件

        Dim wenjian As String = "C:\Users\Administrator\Desktop\pdf文件操作\Test2.pdf"

        ymsum = ymsum + Test.PageCount '统计总的页数

    End If 

Next

Output.Show(ymsum) '输出指定目录下的pdf文件的所有页码数

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编译错误:局部变量不能与包含它的函数同名。

错误代码：Dim Test As pdfSharp.pdf.PdfDocument = pdfSharp.pdf.IO.PdfReader.Open(file, pdfSharp.pdf.IO.PdfDocumentOpenMode.Import) '读取Test1.pdf

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Dim fl As String = ProjectPath & "Test4.pdf"

For Each File As String In FileSys.GetFiles("C:\Users\Administrator\Desktop") '遍历指定目录下的文件

    If FileSys.GetName(File).Contains(".pdf") Then '找到名称中含pdf的文件

        Dim Test1 As pdfSharp.pdf.PdfDocument = pdfSharp.pdf.IO.PdfReader.Open(file1, pdfSharp.pdf.IO.PdfDocumentOpenMode.Import) '读取Test1.pdf

        Dim Proc As New Process '定义一个新的Process

        Proc.File = fl '指定要打开的文件

        Proc.Start()

    End If

Next

Dim filename As String = e.Form.Controls("TextBox1").text

Dim fl As String = ProjectPath & "Test7.pdf"

'Dim watermark As String = "Test Watermark" '定义水印

Dim watermark As String 

Dim font As pdfSharp.Drawing.XFont = New pdfSharp.Drawing.XFont("Verdana", 30, pdfSharp.Drawing.XFontStyle.Bold) '定义水印字体

Dim format As pdfSharp.Drawing.XStringFormat = New pdfSharp.Drawing.XStringFormat()

format.Alignment = pdfSharp.Drawing.XStringAlignment.Near

format.LineAlignment = pdfSharp.Drawing.XLineAlignment.Near

Dim gfx As pdfSharp.Drawing.XGraphics

Dim size As pdfSharp.Drawing.XSize

Dim brush As pdfSharp.Drawing.XBrush

Dim pen As pdfSharp.Drawing.XPen

Dim path As pdfSharp.Drawing.XGraphicsPath 

Dim Test As pdfSharp.pdf.PdfDocument = pdfSharp.pdf.IO.PdfReader.Open(filename, pdfSharp.pdf.IO.PdfDocumentOpenMode.Modify) '读取Test1.pdf

For idx As Integer = 0 To Test.PageCount - 1

    Dim page As pdfSharp.pdf.PdfPage = Test.Pages(idx) '获取页面'

    Dim width As Double = page.Width

    Dim height As Double = page.Height 

    '-------------------------------------------------------------------------------------------------------''

    '  第 1 种: 将水印绘制为文本字符串.

    '获取用于在现有内容下绘制的图形对象

    gfx = pdfSharp.Drawing.XGraphics.FromPdfPage(page, pdfSharp.Drawing.XGraphicsPdfPageOptions.Prepend)

    '获取文本的大小(以磅为单位)

    watermark = idx + 1      

    size = gfx.MeasureString(watermark, font)

    '创建暗红色笔刷

    brush = New pdfSharp.Drawing.XSolidBrush(pdfSharp.Drawing.XColor.FromArgb(128, 255, 0, 0))

    '描绘字符串

'   gfx.DrawString(watermark, font, brush, New pdfSharp.Drawing.XPoint((width - size.Width) / 2, (height - size.Height) / 2), format)

Next

Test.Save(fl) '另存为Test7.pdf

Dim Proc As New Process '定义一个新的Process

Proc.File = fl '指定要打开的文件

Proc.Start()