Microsoft Access 2010 Bible

Part IV: Professional Database Development

1002

FIGURE 28.13

The InvalidSupplierID event appears in the Object Browser.

You’ll notice a couple other events — InsufficientStockAvailable and ProductSold —

in the Product class module. I’ve added the other events in exactly the same manner as the

InvalidSupplierID event. An event declaration is all that’s required to add an event to a

class’s interface. The class module never even has to trigger an event shown in the Object Browser.

Raising events

An event that is never invoked by a class module’s code isn’t much use to anybody. Events are typ-

ically triggered (or raised) whenever circumstances indicate that the consumer should be notified.

Raising an event requires a single line of code:

RaiseEvent <EventName>(<Arguments>)

I discuss event arguments in the “Passing data through events” section, later in this chapter. In the

meantime, take a look at raising the InvalidSupplierID event from the SupplierName

Property Get:

Public Property Get SupplierName() As String

Dim varTemp As Variant

If m_SupplierID <= 0 Then

RaiseEvent InvalidSupplierID()

Exit Property

End If

varTemp = DLookup(“CompanyName”, “Suppliers”, _

“SupplierID = “ & m_SupplierID)

If Not IsNull(varTemp) Then

SupplierName = CStr(varTemp)

Else