Microsoft Access 2010 Bible

Part II: Programming Microsoft Access

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Note
Access event procedures, as seen in the Property Sheet, often contain spaces. For instance, the Open event
appears as the On Open event procedure. The event itself, of course, is Open. Many, but not all, event prop-
erty names begin with On.

You add an event procedure to a form or report by selecting the event property (Before Update,

for this example) in the object’s Property Sheet. If no event procedure currently exists for the prop-

erty, a drop-down arrow and builder button appear in the property’s box, as shown in the Before

Update event property in Figure 12.1.

The drop-down button exposes a short list that contains [Event Property]. Selecting this

option and then clicking on the builder button, takes you to the VBA code editor with an event

procedure template already in place (see Figure 12.2).

FIGURE 12.2

An empty event procedure template for the form’s BeforeUpdate event.

Notice the general format of the event procedure’s declaration:

Private Sub Object_Event()

The Object portion of the procedure’s name is, of course, the name of the object raising the event,

while the Event portion is the specific event raised by the object. In Figure 12.2, the object is Form

and the event is BeforeUpdate. Some events support arguments, which appear within the

parentheses at the end of the declaration.

In case you’re wondering, you can’t change the name, or the arguments, of an event procedure and

expect it to continue working. Access VBA relies on the Object_Event naming convention to tie

a procedure to an object’s event.

Identifying Common Events

Certain events are raised by many different Access objects. Microsoft has taken great care that these

events behave exactly the same way, regardless of the object raising them. Table 12.1 lists several