Reading excel file using OLEDB Data Provider

This worked for me

        using (OleDbConnection conn = new OleDbConnection())
        {
            DataTable dt = new DataTable();
            conn.ConnectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + path
            + ";Extended Properties="Excel 12.0 Xml;HDR=YES;IMEX=1;MAXSCANROWS=0"";
            using (OleDbCommand comm = new OleDbCommand())
            {
                comm.CommandText = "Select * from [" + sheetName + "$]";
                comm.Connection = conn;
                using (OleDbDataAdapter da = new OleDbDataAdapter())
                {
                    da.SelectCommand = comm;
                    da.Fill(dt);
                    return dt;
                }
            }
        }

The MAXSCANROWS=0 overrides the registry default and scans all rows before determining types. IMEX=1 still needs to be included.

For example, given this table:

Header | Header
------ | ------
Cell1  | 2456354
Cell2  | 2456354
Cell3  | 2456354
Cell4  | 2456354
Cell5  | 2456354
Cell6  | 2456354
Cell7  | 2456354
Cell8  | 2456354
Cell9  | A5341

The following connection strings will lose A5341

"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + path 
   + ";Extended Properties="Excel 12.0 Xml;HDR=YES;IMEX=1;""

"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + path
   + ";Extended Properties="Excel 12.0 Xml;HDR=YES;MAXSCANROWS=0""

But it works when it has both.