User`s guide

Creating an Instance of a Class

Function foo(x1 As Variant, x2 As Variant) As Variant

Dim aClass As mycomponent.myclass

On Error Goto Handle_Error

Set aClass = New mycomponent.myclass

' (call some methods on aClass)

Exit Function

Handle_Error:

foo = Err.Description

End Function

In this example, the class instance could be dimensioned as simply myclass.

Thefulldeclarationintheform

<component-name>.<class-name> guards

against name collisions that could occur if other libraries in the current

project contain types named

myclass.

Both methods a re equivalent in functionality. The first method does not

require a reference to the type library in the VBA project, while the second

results in faster code e xecution. The second method has the added advantage

of enabling the Auto-List-Members and Auto-Quick-Info capabilities of

the VBA editor to work with your classes. The default function wrappers

created with each built component all use the first method for object creation.

In the previous two examples, the class instance used to make the method

call was a local v ariable of the procedure. This creates and destroys a new

class instance for each call. An alternative approach is to declar e one single

module-scoped class instance that is reused by all function calls, as in the

initialization code of the previous example.

The following example illustrates this technique with the second method: