Specify a variable implementing 2 interfaces in .net

Question

Is is possible to implement a type specifier with 2 interfaces in .net? Something like:

Public Sub New(obj as ICollection and INotifyCollectionChanged)
    ''Initialize Code
End Sub

Answer 1

No, you will have to define an interface that inherits from both of your desired interfaces.

Public Interface IMyCombinedInterface
    Inherits IColllection, INotifyCollectionChanged

End Interface

Answer 2

You can with generic constraints; for example in c#:

public void Something<T>(T obj)
    where T : IFoo, IBar
{....}

Then Something(value) will work only when value is typed as something that implements both IFoo and IBar.