Generic Class Covariance

Question

Is it possible to make the following code compile in C#? I do compile similar in Java.

public interface IInterface
{
    ...
}

public class Class1 : IInterf         


        

Answer 1

Looks like .NET Framework 4.0 supports covariance in generic interfaces and delegates. So, I happened to compile the code by adding a generic interface.

public interface IInterface
{
    ...
}

public class Class1 : IInterface
{
    ...
}

public interface IBase where T: IInterface
{
    // Need to add out keyword for covariance.
}

public class Base : IBase where T : IInterface
{
    ...
}

public class Class2 : Base where T : IInterface
{
    ...
}

.
.
.

public SomeMethod()
{
    List> list = new List>();
    Class2 item = new Class2();
    list.Add(item); // No compile time error here.
}