title: OLEDB connection does not read data from excel sheet
body: <p>i am getting a weird problem. i am using OLEDB for excel connection with 
  connection string = Provider=Microsoft.Jet.OLEDB.4.0;Data Source=c:\Execute.xls;Extended Properties=Excel 8.0;");</p>
  
  <p>excel file contains columns with string/integer values.
  the problem is that sometimes connection read values from sheet absolutly fine but sometimes it missed out some data values and shows them as System.DBNull.
  the behavior is very inconsistent.
  please help.</p>