Professional .NET 2.0 Generics

7.5. Generic Delegate and Method Constraints

Every generic construct in the .NET Framework provides a mechanism for qualifying its type parameters with constraints. And, from the previous discussion, you've gotten to see plenty of examples where constraints were included as part of a generic class declaration. However, so far, you haven't really seen how constraints are applied to the remaining generic constructs. There's a reason for this. The constraints syntax for each of the remaining constructs is very similar to what you've already seen with generic classes. To illustrate this point, take a quick look at some simple generic delegates and methods with constraints applied to their type parameters:

[VB code]
Public Class MyClass
    Public Delegate Sub MyDelegate(Of T As IValidator)(ByVal val As Int32)

    Public Sub Foo(Of T As IValidator)(ByVal val As T)
    End Sub
End Class

[C# code]
public class MyClass {
    public delegate void MyDelegate<T>(int val) where T : IValidator;

    public void Foo<T>(T val) where T : IValidator {}
}

This probably appears just as you would expect. The C# examples offer a bit more variation, but nothing that's all that different than what you saw with generic classes.