C# csv.excel导入

 string clientFilename = FileUpload1.PostedFile.FileName.ToLower();
            string serverFilename = "";
            if (clientFilename == "")
            {
                return;
            }
            if (clientFilename.ToLower().IndexOf(".xlsx") > 0)
            {
                serverFilename = ".xlsx";
            }
            else
            {
                if (clientFilename.ToLower().IndexOf(".csv") > 0)
                {
                    serverFilename = ".csv";
                }
                else if (clientFilename.ToLower().IndexOf(".xls") > 0 && clientFilename.EndsWith("xls"))
                {
                    serverFilename = ".xls";
                }
                else
                {
                    return;
                }
            }
            string type = serverFilename;
            serverFilename = "~/uploadexcel/" + "Test" + DateTime.Now.Year.ToString()
           + (DateTime.Now.Month > 9 ? DateTime.Now.Month.ToString() : "0" + DateTime.Now.Month.ToString())
           + (DateTime.Now.Day > 9 ? DateTime.Now.Day.ToString() : "0" + DateTime.Now.Day.ToString())
           + (DateTime.Now.Hour > 9 ? DateTime.Now.Hour.ToString() : "0" + DateTime.Now.Hour.ToString())
           + (DateTime.Now.Minute > 9 ? DateTime.Now.Minute.ToString() : "0" + DateTime.Now.Minute.ToString())
           + (DateTime.Now.Second > 9 ? DateTime.Now.Second.ToString() : "0" + DateTime.Now.Second.ToString())
           + DateTime.Now.Millisecond.ToString() + serverFilename;

            serverFilename = MapPath(serverFilename);
            if (File.Exists(serverFilename))
            {
                File.Delete(serverFilename);
            }
            FileUpload1.SaveAs(serverFilename);//上传文件
            if (type == ".csv")
            {
                string c = serverFilename.Substring(0, serverFilename.LastIndexOf(@"\") + 1);//取到文件的上一级路径
                string b = serverFilename.Substring(serverFilename.LastIndexOf(@"\") + 1);//取到文件名           
                string strConn = @"Driver={Microsoft Text Driver (*.txt; *.csv)};Dbq= " + c;
                strConn += ";Extensions=asc,csv,tab,txt;";
                OdbcConnection objConn = new OdbcConnection(strConn);
                DataSet ds = new DataSet();

                try
                {
                    string strSql = @"select * from " + b;
                    OdbcDataAdapter odbcCSVDataAdapter = new OdbcDataAdapter(strSql, objConn); 
                    odbcCSVDataAdapter.Fill(ds);
                }
                catch (Exception ex)
                {
                    throw ex;
                }
            }
            else if(type==".xls" || type==".xlsx")
            {
                DataSet ds = new DataSet();
                string sconn="";
                if (type == ".xls")
                {
                    sconn = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source='" + serverFilename + "';Extended Properties='Excel 8.0;HDR=YES;'";
                }
                else
                {
                    sconn = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source='" + serverFilename + "';Extended Properties='Excel 12.0;HDR=YES'";
                }
                OleDbConnection conn = new OleDbConnection(sconn);
                OleDbDataAdapter odda = new OleDbDataAdapter("select * from [Sheet1$]", conn);
                odda.Fill(ds);
            }