我如何从asp.net c＃

Question

This is my Upload Button Code. I want to upload pdf file and then read all the files that is uploaded. 


 protected void Upload_Files(object sender, EventArgs e)
            {
                if (fileUpload.HasFile)     // CHECK IF ANY FILE HAS BEEN SELECTED.
                {
                    int iUploadedCnt = 0;
                    int iFailedCnt = 0;
                    HttpFileCollection hfc = Request.Files;
                    lblFileList.Text = "Select <b>" + hfc.Count + "</b> file(s)";

                    if (hfc.Count <= 10)    // 10 FILES RESTRICTION.
                    {
                        for (int i = 0; i <= hfc.Count - 1; i++)
                        {
                            HttpPostedFile hpf = hfc[i];
                            if (hpf.ContentLength > 0)
                            {
                                if (!File.Exists(Server.MapPath("CopyFiles\\") +Path.GetFileName(hpf.FileName)))
                                {
                                    DirectoryInfo objDir = new DirectoryInfo(Server.MapPath("CopyFiles\\"));

                                    string sFileName = Path.GetFileName(hpf.FileName);
                                    string sFileExt = Path.GetExtension(hpf.FileName);

                                    // CHECK FOR DUPLICATE FILES.
                                    FileInfo[] objFI = objDir.GetFiles(sFileName.Replace(sFileExt, "") + "*.pdf");

                                    if (objFI.Length > 0)
                                    {
                                        // CHECK IF FILE WITH THE SAME NAME EXISTS 

                                        foreach (FileInfo file in objFI)
                                        {
                                            string sFileName1 = objFI[0].Name;
                                            string sFileExt1 = Path.GetExtension(objFI[0].Name);

                                            if (sFileName1.Replace(sFileExt1, "") == sFileName.Replace(sFileExt, ""))
                                            {
                                                iFailedCnt += 1;        // NOT ALLOWING DUPLICATE.
                                                break;
                                            }
                                        }
                                    }
                                    else
                                    {
                                        // SAVE THE FILE IN A FOLDER.
                                        hpf.SaveAs(Server.MapPath("CopyFiles\\") + Path.GetFileName(hpf.FileName));
                                        iUploadedCnt += 1;
                                    }
                                }
                            }
                        }
                        lblUploadStatus.Text = "<b>" + iUploadedCnt + "</b> file(s) Uploaded.";
                        lblFailedStatus.Text = "<b>" + iFailedCnt + "</b> duplicate file(s) could not be uploaded.";
                    }
                    else lblUploadStatus.Text = "Max. 10 files allowed.";
                }
                else lblUploadStatus.Text = "No files selected.";



            }

当我使用iTextSharp.text.pdf.parser使用库时，我在此方法中遇到Path.GetExtension（hpf.FileName ）错误;在我的代码中。我正在使用Path.GetExtension（hpf.FileName）从浏览器上传文件。

                          if (!File.Exists(Server.MapPath("CopyFiles\\") +Path.GetFileName(hpf.FileName)))
                            {
                                DirectoryInfo objDir = new DirectoryInfo(Server.MapPath("CopyFiles\\"));

                                string sFileName = Path.GetFileName(hpf.FileName);
                                string sFileExt = Path.GetExtension(hpf.FileName);

                                // CHECK FOR DUPLICATE FILES.
                                FileInfo[] objFI = objDir.GetFiles(sFileName.Replace(sFileExt, "") + "*.pdf");

                                if (objFI.Length > 0)
                                {
                                    // CHECK IF FILE WITH THE SAME NAME EXISTS 

                                    foreach (FileInfo file in objFI)
                                    {
                                        string sFileName1 = objFI[0].Name;
                                        string sFileExt1 = Path.GetExtension(objFI[0].Name);

                                        if (sFileName1.Replace(sFileExt1, "") == sFileName.Replace(sFileExt, ""))
                                        {
                                            iFailedCnt += 1;        // NOT ALLOWING DUPLICATE.
                                            break;
                                        }
                                    }
                                }
                                else
                                {
                                    // SAVE THE FILE IN A FOLDER.
                                    hpf.SaveAs(Server.MapPath("CopyFiles\\") + Path.GetFileName(hpf.FileName));
                                    iUploadedCnt += 1;
                                }
                            }