Visual Basic 2015 Unleashed

Passing Interfaces as Method Arguments

One of the most powerful features when working with interfaces is that methods can receive interfaces as parameters. This means that you can pass in any object as these parameters so long as it implements the given interface. The following example shows a method that accepts an argument of type IList, meaning that any object implementing the IList interface can be accepted:

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'Interfaces as parametersPublic Class WorkWithLists    Public Function Elaborate(items As IList) As Integer        'Just for demo, returns 0 if the list contains something        If items.Count > 0 Then            Return 0        Else            'if not, adds a new object to the list            Dim item As ...