Determine if Equals() is an override?

问题:

I have an instance of Type (type). How can I determine if it overrides Equals()?

回答1:

private static bool IsObjectEqualsMethod(MethodInfo m)
{
    return m.Name == "Equals"
        && m.GetBaseDefinition().DeclaringType.Equals(typeof(object));
}

public static bool OverridesEqualsMethod(this Type type)
{
    var equalsMethod = type.GetMethods()
                           .Single(IsObjectEqualsMethod);

    return !equalsMethod.DeclaringType.Equals(typeof(object));
}

Note that this reveals whether object.Equals has been overridden anywhere in the inheritance hierarchy of type. To determine if the override is declared on the type itself, you can change the condition to

equalsMethod.DeclaringType.Equals(type)

EDIT: Cleaned up the IsObjectEqualsMethod method.

回答2:

If you enumerate all methods of a type use BindingFlags.DeclaredOnly so you won't see methods which you just inherited but not have overridden.