ActiveX controls can be programmed to respond to events. You can use ClassWizard to view the events that are available in a control and to create event handlers. Event handling is commonly done to trap changes in the data-source query. Changes include:
Implementing a Lookup: When a control (like a DBCombo box) changes value, the change event is trapped to update a data-source control's query.
Implementing a Master Detail Relationship: Two data-source controls are added to a dialog box, one for the master portion and a second for the detail portion. Whenever the first data source changes, the second data source's query is updated via an event handler.
Trapping errors: Most controls have an error event from which you can write an error handler. See Error Trapping.
See Mapping Messages to Functions, for more information.
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