Designing the Procedure Logic › GUI Event Processing › Windows and Window Controls That Signal Events › CHANGED GUI Event

CHANGED GUI Event

The CHANGED event is triggered when a user's actions cause data in the import view to change.

The CHANGED event is triggered for the following actions:

• Tabbing off an entry field after editing it
• Clicking on an unselected radio button or check box
• Selecting a different item from a drop-down list
• Clicking on an unselected row in a list box

The event handler runs after the import view has been updated with new data.

The CHANGED event is provided to allow actions such as validation of fields as they are entered and population of other fields as a result of changing a field. The user expects instant (or, nearly instant) response time when they tab. Processing in changed events should meet this expectation.

Before any logic is coded in-line in the event handler, you should ask, “Can this logic be reused?” If the answer is yes, then you should construct an action block to contain the logic.

The next sample code shows validating a department if the key is changed in a dialog box.