Question

Ive the following code:

    TConverted ret;
    ret = forward.Get<TConverted>(GetForwardKey(id, convType));
    if (ret != default(TConverted))... // wrong here !

the generic Get function returns an item from a cache. It can be a value type or a class. I would like to check if the returned value is null or the default, but the code I guess it should work it does not. Is it possible to do?

Answer 1

From this essentially-identical question…

To avoid boxing, the best way to compare generics for equality is with
EqualityComparer<T>.Default. This respects IEquatable<T> (without
boxing) as well as object.Equals, and handles all the Nullable<T>
“lifted” nuances. Hence:

if(EqualityComparer<T>.Default.Equals(obj,default(T)) {
    return obj;
}

This will match:

• null for classes
• null (empty) for Nullable<T>
• zero/false/etc for other structs

If this is helpful to you, please upvote Mark Gravell’s answer (which I’ve quoted) on the question I linked to.