Creating Properties

To create a property, you add a Property statement. Private member variables are accessible only from outside the class when the Get and Set property procedures are accessed. These private member variables are also known as fields. The Get property procedure returns the value of the field, and the Set property procedure enables you to assign a value to the field. You can create a property in Visual Basic by typing the Property statement, such as the following, and then pressing the ENTER key.

Property Text() as String

Visual Basic automatically creates the Get and Set statements for you, as the code example in Listing 3.1 shows.

Listing 3.1. Creating a property

Property Text() As String Get

End Get

Set(ByVal value As String)

End Set End Property

Notice that the value field is created for you as a parameter of the Set property procedure. To assign the value to the member variable in the Set property procedure, you must create a member variable and write code. You must also write code to return the member variable in the Get property procedure. You can create a read-only property by using the ReadOnly keyword before the property. In the case of a read-only property, you need only provide a Get property procedure.

So far, the Text property you created lets you set and get a value for the Text property. You cannot use these properties or store any data in the class until you have actually created an instance of the class (an object). Each object that you create can hold a different value for the Text property.

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