public string SaveUploadExcel(HttpPostedFile hpf)//验证Excel文件的正确性
  {
       //检查文件格式各文件大小是否有效
       if(hpf == null || hpf.ContentLength < 1 || System.IO.Path.GetExtension(hpf.FileName).ToLower() != ".xls")
       {
            throw new InnerException("文件上传失败或文件格式不正确。！");
       }

       //保存文件
       try
       {
            string fileFullName = MakeFileName();
            hpf.SaveAs(fileFullName);
            return fileFullName;
       }
       catch//(Exception ex)
       {
            throw new InnerException("保存文件失败。");// + ex.Message);
       }
  }

  public string MakeFileName()//生成唯一文件名的Excel文件
  {
       string filePath = HttpContext.Current.Server.MapPath(HttpContext.Current.Request.ApplicationPath)         +"\\uploadFiles\\PlanExcel";
       if(!Directory .Exists(filePath))
            Directory.CreateDirectory(filePath);
       string fileName = Convert.ToString(HttpContext.Current.Session["UserID"])  + "_"
        + DateTime.Now.ToString("yyyyMMddHHmmss")
        + ".xls";

       return filePath + "\\" + fileName;
  }

public DataTable ReadNoHeadExcelData(string fileFullName)//读取Excel文件最后返回一个DataTable，可以在返回DataTable后对这个DataTable进行检验！
  {
        string excelNoHeadConnStr = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source={0};Extended Properties=\"Excel 8.0;HDR=NO;IMEX=1;\"";//连接字符串
       OleDbConnection oleCn =new OleDbConnection();
       try
       {
            string currConnStr = string.Format(excelNoHeadConnStr, fileFullName);//连接字符串
            oleCn.ConnectionString = currConnStr;                    
            DataTable dt = new DataTable();
            oleCn.Open();
            string excelBookName = oleCn.GetOleDbSchemaTable(System.Data.OleDb.OleDbSchemaGuid.Tables, null).Rows[0][2].ToString();
            if(excelBookName!=string.Empty && excelBookName.Trim()!="")
            {
                 string currSqlStr = string.Format(excelSqlStr, excelBookName);//sql字符串
                 OleDbCommand oleCmd = new OleDbCommand(currSqlStr, oleCn);
                 OleDbDataAdapter oleDda = new OleDbDataAdapter(oleCmd);
                 oleDda.Fill(dt);               
            }
            oleCn.Close();                
            return dt;
       }
       catch
       {
            string errorMsg="Excel文件格式不对,请尝试用excel打开该文件检查内容并另存一下,确保成为正确的excel文件,再重新上传";
            System.Web.HttpContext.Current.Response.Write("<script>alert('"+ errorMsg  +"')</script>");
            oleCn.Close(); 
            return null;
        }
  }