User Input in Combo Boxes
The combo box control has the functionality of a list box and a text box. There are two styles for a combo box: Drop-down combo and Drop-down list. Specify which one you want by changing the Style property of the control. Drop-down lists are discussed in Controls for Displaying Lists.
Drop-Down Combo Box
A user can click the button on a drop-down combo box to see a list of choices or enter a new item directly in the box beside the button. The default Style property of a combo box is 0 — Dropdown Combo.
Adding User Items to Drop-Down Combo Box Lists
To add the new user value to the drop-down combo box, you can use the following line of code in the method associated with the Valid event of the combo box:
THIS.AddItem(THIS.Text)
Before adding an item, however, it would be a good idea to check to make sure that the value is not already in the combo box drop-down:
lItemExists = .F. && assume the value isn't in the list.
FOR i = 1 to THIS.ListCount
IF THIS.List(i) = THIS.Text
lItemExists = .T.
EXIT
ENDIF
ENDFOR
IF !lItemExists
THIS.AddItem(THIS.Text)
ENDIF
Common Combo Box Properties
The following combo box properties are commonly set at design time.
Property |
Description |
|---|---|
Specifies the table field where the value that the user chooses or enters is stored. |
|
Specifies the maximum number of items displayed in the list. |
|
For drop-down combo boxes, specifies the type of values that can be typed in. |
|
Specifies whether the control tries to match an item in the list as the user types each letter. |
|
Specifies the source of the items in the combo box. |
|
Specifies the type of the source for the combo box. The RowSourceType values for a combo box are the same as for a List. |
|
Specifies whether the combo box is a drop-down combo or a drop-down list. |