Ci#导入电子表格问题

Ci#导入电子表格的时候，datatables.Rows.count=0了，电子表格式有数据的，具体的语句如下：
 DataTable ExcelTable;  
             DataSet ds = new DataSet();
             //Excel的连接
  
            // OleDbHelper.ExecuteNonQuery(OleDbConnection OleDbHelper.
            OleDbConnection objConn = new  OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" +
                       sExcelFile + ";" + "Extended Properties=Excel 8.0;");
            objConn.Open();  
            DataTable schemaTable =  objConn.GetOleDbSchemaTable(System.Data.OleDb.OleDbSchemaGuid.Tables, null);

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