How to get a gridview to show all table rows when no text is entered in a dependent textbox?

Question

The below works correctly and filters my gridview based on the text entered in my textbox.

When no text is entered into my textbox I get no results and cannot unders

Answer 1

Look at CancelSelectOnNullParameter - by default, this prevents the select command from being called when a select parameter's value is null. After setting it to false, the select SP will then still get called even if the text box is empty, e.g.

The SqlDataSource seems a bit misleading to me here, because TextBox.Text returns String.Empty when it's empty, not null, therefore I wouldn't expect to have to mess with CancelSelectOnNullParameter for a TextBox, but it seems we have to.