打开pdf文档时出现错误

我正在使用网页中的母版页，当我打开pdf文件时，在脚本编写中会产生错误

错误在下面给出

I am using master page in a web page and When i opening the pdf file, The error is generated in scripting

The error is given below

Microsoft JScript runtime error: Sys.WebForms.PageRequestManagerParserErrorException: The message received from the server could not be parsed. Common causes for this error are when the response is modified by calls to Response.Write(), response filters, HttpModules, or server trace is enabled.
Details: Error parsing near '%PDF-1.4
%��2 0 obj '

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我打开pdf的代码如下所示

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My code to open pdf is given below

Public Sub ExportToPdf(ByVal ExDataTable As DataTable)
        'Here set page size as A4

        Dim pdfDoc As New Document(PageSize.A4, 10, 10, 10, 10)

        Try
            PdfWriter.GetInstance(pdfDoc, System.Web.HttpContext.Current.Response.OutputStream)
            pdfDoc.Open()

            'Set Font Properties for PDF File
            Dim fnt As Font = FontFactory.GetFont("Times New Roman", 12)
            Dim dt As DataTable = ExDataTable
            'dt.Columns(0).ColumnName = "A"
            'dt.Columns(1).ColumnName = "B"
            'dt.Columns(2).ColumnName = "c"
            'dt.Columns(3).ColumnName = "d"


            If dt IsNot Nothing Then
                '----
                Dim tblHeader As New PdfPTable(4)
                tblHeader.WidthPercentage = 85
                tblHeader.SetWidths(New Integer(3) {1, 1.8, 1, 1})
                Dim cellDocHdr As New PdfPCell(New Phrase("Order Summary"))
                cellDocHdr.Colspan = 4
                cellDocHdr.HorizontalAlignment = 1
                cellDocHdr.Border = 0
                tblHeader.AddCell(cellDocHdr)
                pdfDoc.Add(tblHeader)

                Dim tblBlank As New PdfPTable(4)
                Dim cellBlank As New PdfPCell(New Phrase(" "))
                cellBlank.Colspan = 4
                cellBlank.HorizontalAlignment = 1
                cellBlank.Border = 0
                tblBlank.AddCell(cellBlank)
                pdfDoc.Add(tblBlank)
                '--

                Dim PdfTable As New PdfPTable(dt.Columns.Count)
                'PdfTable.SetWidths(New Single(6) {0.5, 0.9, 1.5, 2.5, 1, 1, 0.8})
                PdfTable.SetWidths(New Single(6) {2.0, 1.5, 1.5, 1.5, 2.0, 2.0, 2.0})
                PdfTable.WidthPercentage = 102
                Dim PdfPCell As PdfPCell = Nothing

                'Here we create PDF file tables

                For rows As Integer = 0 To dt.Rows.Count - 1
                    If rows = 0 Then
                        For column As Integer = 0 To dt.Columns.Count - 1
                            PdfPCell = New PdfPCell(New Phrase(New Chunk(dt.Columns(column).ColumnName.ToString(), fnt)))
                            PdfPCell.HorizontalAlignment = 1
                            PdfTable.AddCell(PdfPCell)
                        Next
                    End If
                    For column As Integer = 0 To dt.Columns.Count - 1
                        PdfPCell = New PdfPCell(New Phrase(New Chunk(dt.Rows(rows)(column).ToString(), fnt)))
                        PdfPCell.HorizontalAlignment = 1
                        PdfTable.AddCell(PdfPCell)
                    Next
                Next

                ' Finally Add pdf table to the document 
                pdfDoc.Add(PdfTable)
            End If

            pdfDoc.Close()

            Response.ContentType = "application/pdf"

            'Set default file Name as current datetime
            Response.AddHeader("content-disposition", "attachment; filename=" & DateTime.Now.ToString("yyyyMMdd") & ".pdf")

            System.Web.HttpContext.Current.Response.Write(pdfDoc)

            Response.Flush()

            Response.End()
        Catch ex As Exception
            Response.Write(ex.ToString())
        End Try
    End Sub