Covariance
Covariance enables you to assign strongly typed collections (such as List
) of derived classes to IEnumerable
collections of abstract classes. The code in Listing 20.4 shows how covariance works.
Module Covariance Sub Main() 'Using collection initializers Dim stringsCollection As New List(Of String) _ From {"Understanding ", "covariance ", "in VB 2015"} 'This code is now legal Dim variance As IEnumerable(Of Object) = stringsCollection For Each s In variance Console.WriteLine(s) Next Console.ReadLine() End SubEnd Module
If you examine Listing 20.4, you see that the ...
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