Selection list in a text box
You can use selection lists in text boxes, which improves their usability.
A text box that has a reference type, such as Warehouse or Employee, by default includes a selection button that opens the selection form for a referenced object.
You might need to implement a similar selection from a set of predefined values for fields of other types.
Let us review a very simple example where a user needs to enter customer addresses starting with city names.