Sys.WebForms.PageRequestManagerParserErrorException解决方法之一

有这样一功能,点击Web页面上的按钮,从DB中取出数据,写到Excel中,然后再从服务器上下载这个Excel文件到客户端.

代码如下:

1.页面代码如下:
<%@ Page Language="C#" MasterPageFile="~/DefaultMaster.master" AutoEventWireup="true" CodeFile="P0204.aspx.cs" Inherits="Page_P0204" Title="Employee Information Searching" StylesheetTheme="Default" %> <asp:Content ID="mainContent" ContentPlaceHolderID="SampleContent" runat="Server" > <mce:script language="javascript" type="text/javascript" src="../Js/P0101.js" mce_src="Js/P0101.js"><!-- // --></mce:script> <%-- other controls--%> <table cellspacing="1" cellpadding="0" border="0"> <tbody> <tr> <td style="width: 45px; height: 570px"></td> <td style="width: 91px; height: 57px" align="right"> <asp:UpdatePanel id="upPanel_Revision" runat="server" UpdateMode="Conditional"> <contenttemplate> <asp:Button id="btnOutput" runat="server" Text="EXCEL Download" Width="80px" Height="20px" Font-Size="9pt" OnClick="btnOutput_Click" ></asp:Button> </contenttemplate> </asp:UpdatePanel> </td> </tr> </tbody> </table> </asp:Content>

2.服务器端代码如下:

using System; using System.Data; using System.Configuration; using System.Collections; using System.Web; using System.Web.Security; using System.Web.UI; using System.Web.UI.WebControls; using System.Web.UI.WebControls.WebParts; using System.Web.UI.HtmlControls; using System.IO; using System.Collections.Generic; using System.Runtime.InteropServices; using System.Diagnostics; using System.Drawing; //********其他头文件 //using other.header.file protected void btnOutput_Click(object sender, EventArgs e) { try { string strYear = this.lstYear.SelectedValue.Trim(); string strSeason = this.lstSeason.SelectedValue.Trim(); string strDptType = this.lstDpt.SelectedValue.Trim(); //grd_employee为页面上显示员工信息的一个gridview foreach (GridViewRow grdRow in this.grd_employee.Rows) { if (((CheckBox)(grdRow.Cells[4]).FindControl("ckb_Output")).Checked == true) { string strLocalEmpNo = ((LinkButton)(grdRow.Cells[1].Controls[0])).Text.ToString(); string strLocalEmpName = (grdRow.Cells[2]).Text.ToString(); string strLocalEmpLevel = (grdRow.Cells[3]).Text.ToString(); //write to excel if (false == writeToExcel(strYear, strSeason, strLocalEmpNo, strLocalEmpLevel, strLocalEmpName, strDptType)) { //error message string msg = Messages.GetMessage("I_P0403_001", strLocalEmpNo, strLocalEmpName); SystemLog.Error(Messages.GetMessage("E_P0403_001", strLocalEmpNo)); ScriptManager.RegisterStartupScript(Page, this.GetType(), String.Empty, "alert('" + msg + "');", true); } else { string strFileName = Session["fullName"].ToString(); FileDownload(strFileName, strLocalEmpNo, strLocalEmpName); } //因为FileDownload函数只能下载一个文件,所以这里就这样处理, break; } } } catch (System.Exception ex) { //实际工程中所定义的处理异常函数 ExceptionHandler.HandleException(ex); } finally { System.GC.Collect(); } } [DllImport("User32.dll", CharSet = CharSet.Auto)] public static extern int GetWindowThreadProcessId(IntPtr hwnd, out int ID); /// <summary> /// 把从DB中取得的数据写入EXCEL文件中,EXCEL文件格式已固定. /// </summary> /// <param name="strYear">年</param> /// <param name="strSeason">季度</param> /// <param name="strEmpNo">员工号</param> /// <param name="strEmpLevel">员工级别</param> /// <param name="strEmpName">员工名字</param> /// <param name="strDptType">员工所在部门类别</param> /// <returns>true/false</returns> public Boolean writeToExcel(string strYear, string strSeason, string strEmpNo, string strEmpLevel, string strEmpName, string strDptType) { //定义一个Excel程序对象 Excel.ApplicationClass excelApp = new Excel.ApplicationClass(); Excel.Worksheet excelWorkSheet = new Excel.Worksheet(); try { DataTable tblEvalutionInfo = new DataTable(); tblEvalutionInfo = _b0204.GetEvalutionInfo(strYear, strSeason, strEmpNo); //定义一个缺少的object对象 object oMis = System.Reflection.Missing.Value; //由Execl程序创建一个工作薄对象 string strEvaFormatFile = ConfigManager.GetAppConfig("InterviewFormatFileName"); string strServerPath = ConfigManager.GetAppConfig("Web.TempFile.Path"); strServerPath = Server.MapPath(String.Format(strServerPath, strEvaFormatFile)); Excel.Workbook excelWorkBook = excelApp.Workbooks.Open(strServerPath, oMis, oMis, oMis, oMis, oMis, oMis, oMis, oMis, oMis, oMis, oMis, oMis, oMis, oMis); //由工作薄对象创建一个工作表 excelWorkSheet = (Excel.Worksheet)excelWorkBook.Worksheets[1]; //设置工作的表的名字 excelWorkSheet.Name = strEmpName; //*********************************** //向EXCEL中写入数据--------开始 //*********************************** //员工号,姓名 string strTemp = strEmpNo + "/" + strEmpName; ((Excel.Range)excelWorkSheet.Cells[1, 1]).set_Item(2, 3, strTemp); //tblEvalutionInfo中的数据写往EXCEL的其他Cells中. //*********************************** //向EXCEL中写入数据--------结束 //*********************************** string strTempFileName = Session.SessionID + System.DateTime.Now.ToString("yyyyMMdd_HHmmss_fffff") + ".xls"; string address = @ConfigManager.GetAppConfig("Web.Temp.Path") + strTempFileName; //在Session中存入临时文件名,Session结束时删除这些临时文件 Session["fullName"] = Server.MapPath(address).ToString(); excelWorkSheet.SaveAs(Server.MapPath(address), oMis, oMis, oMis, oMis, oMis, oMis, oMis, oMis, oMis); if (excelWorkSheet != null) { System.Runtime.InteropServices.Marshal.ReleaseComObject(excelWorkSheet); } if (excelWorkBook != null) { System.Runtime.InteropServices.Marshal.ReleaseComObject(excelWorkBook); } if (excelApp != null) { excelApp.Workbooks.Close(); excelApp.Quit(); System.Runtime.InteropServices.Marshal.ReleaseComObject(excelApp); } excelWorkSheet = null; excelWorkBook = null; excelApp = null; } catch (Exception ex) { //实际工程中所定义的处理异常函数 ExceptionHandler.HandleException(ex); //close excel file if (excelWorkSheet != null) { System.Runtime.InteropServices.Marshal.ReleaseComObject(excelWorkSheet); } if (excelApp != null) { excelApp.Workbooks.Close(); excelApp.Quit(); System.Runtime.InteropServices.Marshal.ReleaseComObject(excelApp); } return false; } return true; } /// <summary> /// 从服务器上下载文件到客户端 /// </summary> /// <param name="FullFileName">所要下载文件在服务器上的全路径</param> /// <param name="strEmpNo">员工号</param> /// <param name="strEmpName">员工姓名</param> /// <returns>无</returns> protected void FileDownload(string FullFileName, string strEmpNo, string strEmpName) { //下载到客户端时的文件名. string fileName = String.Format(Evaluation.Fw.Constants.BusinessConstants.formatInterviewFileName, this.lstYear.SelectedValue.Trim(), this.lstSeason.SelectedValue.Trim(), strEmpName, strEmpNo); System.IO.FileInfo fileInfo = new System.IO.FileInfo(FullFileName); if (fileInfo.Exists == true) { const long ChunkSize = 102400; byte[] buffer = new byte[ChunkSize]; Response.Clear(); System.IO.FileStream iStream = System.IO.File.OpenRead(FullFileName); long dataLengthToRead = iStream.Length; Response.ContentType = "application/octet-stream"; Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(fileName)); while (dataLengthToRead > 0 && Response.IsClientConnected) { int lengthRead = iStream.Read(buffer, 0, Convert.ToInt32(ChunkSize)); Response.OutputStream.Write(buffer, 0, lengthRead); Response.Flush(); dataLengthToRead = dataLengthToRead - lengthRead; } Response.Close(); } }

这时,就产生Sys.WebForms.PageRequestManagerParserErrorException这个异常,具体截图如下:

具体原因不清楚,然后对比本工程中其他类似功能,发现是页面上的EXCEL Download(ID为btnOutput)按钮处于一个UpdatePanel中,就产生这样异常,调试发现,这个异常是由下载产生的,因为临时文件已在服务器上生成,只是没有下载到客户端,于是就在页面和下载函数处找原因.至于为什么时候会产生这样的异常,水平有限,还没有调查出来.但是知道,若把UpdatePanel去掉,即可实现所需功能.

修改之后的页面代码为:

<%@ Page Language="C#" MasterPageFile="~/DefaultMaster.master" AutoEventWireup="true" CodeFile="P0204.aspx.cs" Inherits="Page_P0204" Title="Employee Information Searching" StylesheetTheme="Default" %> <asp:Content ID="mainContent" ContentPlaceHolderID="SampleContent" runat="Server" > <mce:script language="javascript" type="text/javascript" src="../Js/P0101.js" mce_src="Js/P0101.js"><!-- // --></mce:script> <%-- other controls--%> <table> <tr> <td class="" align ="right" style =" width:360px"> <asp:Button ID="btnOutput" runat="server" Text="EXCEL Download" CssClass="commonbutton" Width="90px" OnClick="btnOutput_Click"/> </td> </tr> </table> </asp:Content>

这样,在点击EXCEL Download(ID为btnOutput)按钮时,即可把文件从服务器上下载下来.