Problems of reading Excel 2003 using Oledb

I trie开发者_StackOverflowd to use Oledb to open Excel 2003. Looks like I can read most of data, but for some cells (such as number), the value returned is Null. Any suggestion?

My connection string: ConnectionString="Provider=Microsoft.Jet.OLEDB.4.0;Extended Properties=Excel 8.0;"

You might need to add ";IMEX=1" to the connection string. That tells the driver to read "intermixed" (numbers, dates, strings etc) data columns as text.