Casting generic type “as T” whilst enforcing the type of T

Question

I\'m missing a trick here I think and can\'t believe I\'ve never done this before. However, how can I cast a generic type using the as keyword?

[Serializable]
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Answer 1

where T : class, ISessionManager

you can go even further

where T : class, ISessionManager, new()

this will force non abstract class with parameterless ctor to be handed in as T

Answer 2

Read up on Constraints on Type Parameters in C#.

In this particular case, you must ensure that T is a class:

public abstract class SessionManager<T>
    where T : class, ISessionManager

Answer 3

... where T : class, ISessionManager

In case you want to use the where keyword on methods here is an example that also uses generics

    public void store<T>(T value, String key)
    {
        Session[key] = value;
    }

    public T retrieve<T>(String key) where T:class
    {
        return  Session[key] as T ;
    }