Question

In our application, we are adding a row to a datatable. I would like to validate the row before it is added to the table, and if the data doesn’t meet business requirements, the row does not get added.
I would think RowChanging even is where I need to add validation code. However, how do I prevent the row from being added to the DataTable?

Answer 1

I think the only way you can stop a row from being added in the RowChanging event handler is to throw an Exception:

if (e.Action == DataRowAction.Add) {
    if (e.Row["SomeColumn"].ToString() == "AnInvalidValue") {
        throw new InvalidOperationException("You can't do that.");
    }
}

You’d obviously have to catch this exception and handle it gracefully.

A better approach would be to do your validation in the UI before attempting to add the new DataRow.