Filter records in Base form based on control

I would like to create a Base form with the following basic layout:

  • A text box in which the user can enter a search term (could also be a combo box with predefined values)
  • A grid control which shows matching records, i.e. where a particular column begins with the search term

The approach I have in mind is:

  • The data source for the form is the table holding the records to show in the grid.
  • The text box is not bound to a data field.
  • Search is implemented through filtering, equivalent to something like WHERE "someTable"."someColumn" LIKE ("textBoxValue" + '%')

If the text box is empty, either everything or nothing can match—this is not really important.

Of course I could create a macro that sets the appropriate filter on the form whenever the contents of the text box change.

However, I was wondering if there is a simpler way to achieve this, i.e. without macros. Can I reference the contents of the text box in the filter expression? How? Will changes to the text box be reflected immediately?