I am importing an Excel file into a data table via OleDBDataAdapter. I then process the new data table for data validation. The problem is that during the oledb import the data type for a column is automatically set to 'double' if the column data happens to contain numeric data. In my case, all rows in that column are NULL except for two - one contains text and the other is all numeric. For some reason, the data for that column is determined to be 'double'. All columns are assumed to be 'text'. This poses a problem when I do my validation because I am comparing the value to an expected text value which throws an error saying that the column is expected to be of type 'double'.
Following (or during) the oledb import into the data table, is there some way I can force all columns to be 'text' before I begin my validation process?