Question

I have a DataTable resultSet; – I’m trying to check fields for null, but get an ‘{}’ (empty-set ?) object back. Searches involving ‘{}’ aren’t yielding any appropriate solutions.

This is the code that isn’t working as expected when the ‘fk_id’ field is null:

if (resultSet.Rows[0].ItemArray[resultSet.Columns.IndexOf('fk_id')] == null) {    //never reaches here } 

Note: using an int index instead of the Columns.IndexOf() isn’t the issue.

Also does the ‘{}’ have some other name in C#?

Answer 1

To check a column for DBNull in a DataSet, you can use the IsNull method:

if (resultSet.Rows[0].IsNull('fk_id')) 

Your comparison against null is probably failing because DataSets don’t use null to represent a ‘database NULL’ value – they use DBNull.Value. If you need your code to work the way you’ve presented it, try this:

if (resultSet.Rows[0].ItemArray[resultSet.Columns.IndexOf('fk_id')] == DBNull.Value)