Creating Property Procedures
Public module-level variables in a class module function as properties of an object. However, they're not very sophisticated. If you must run code to set or return a property's value, or you want to make a property read-only, you can create a Property procedure. There are three types of Property procedures: Property Get, Property Let, and Property Set procedures. The Property Get procedure returns the current value of a property, whereas the Property Let procedure sets the value. The Property Set procedure assigns an object to an object property.
To create a read-write property, you must include a pair of Property procedures in the class module. Both procedures must have the same name. If the property stores and returns a scalar value, such as a numeric, text, or date value, you use a Property Let procedure to set the value and a Property Get procedure to retrieve it. If the property stores and returns a reference to an object, you use the Property Set procedure to store the reference and the Property Get procedure to return it.
In addition, you can create read-only, write-only, and write-once properties. The following table outlines which property procedures you must have for each type.
| Type of property | Procedures needed |
|---|---|
| Read-write, scalar | Property Let, Property Get |
| Read-write, object | Property Set, Property Get |
| Read-only, scalar | Property Get |
| Read-only, object | Property Get |
| Write-only, scalar | Property Let |
| Write-once, scalar | Property Let, including code to determine whether property has been set previously, Property Get |
| Write-once, object | Property Set, including code to determine whether object property has been set previously, Property Get |
See Also
Why Build Your Own Objects? | Creating Scalar Properties | Creating Object Properties | Basic Class Concepts | Creating Events and Event Procedures | Extending Objects Through Interfaces | Designing Object Models | Creating Custom Objects for Web Pages