Hi Patrick,

There are any number of ways you could do it depending on the behavior you want.

Typically, if you don't want to allow nulls in a particular field, your data source would handle this. A DataTable or UltraDataSource both have properties on the column object which determines whether null is allowed.

But, if you want to do your validation in the grid, you could do it using the UltraWinValidator component. There's a sample of this component in the NetAdvantage SDK.

Another option would be to handle an event of the grid such as BeforeCellUpdate, BeforeRowUpdate, or BeforeExitEditMode.