Why I cannot pass a method delegation into GetOrAdd() method in concurrent dictionary?

I have defined the below concurrent dictionary:(because reflection is slow so cached it)

  private static ConcurrentDictionary<Type, MethodInfo> dic = new();

then I wanted to get a method from a type and invoke it.

public void Update(TITarget target)
        {
            var methodInfo = dic.GetOrAdd(typeof(TITarget), ()=> getMethodInfo);

            methodInfo.Invoke(target, new object[] { this });
        }

private static MethodInfo getMethodInfo()
        {
            var types = getInheritanceHierarchy(typeof(TITarget));

            var findUpdateMethod = typeof(TITarget)
                .GetMethods(BindingFlags.Public | BindingFlags.Instance).
                   Where(x => x.Name == "Update");

            var methodInfo = types.Join(
                            findUpdateMethod, t => t.Name,
                            mi => mi.DeclaringType.Name,
                            (t, mi) => mi)
                            .First();
            return methodInfo;
        }

        private static IEnumerable<Type> getInheritanceHierarchy(Type type)
        {
            for (var current = type; current != null; current = current.BaseType)
            {
                yield return current;
            }
        }

but i cannot pass a method to the type of MethodInfo and i got the below compile time error:

Severity Code Description Project File Line Suppression State
Error CS1593 Delegate ‘Func<Type, MethodInfo>’ does not take 0 arguments.

how can i fix that issue?

thank you in advance.

>Solution :

dic.GetOrAdd(typeof(TITarget), ()=> getMethodInfo)

You probably want either

 dic.GetOrAdd(typeof(TITarget), getMethodInfo())

or, arguably better:

dic.GetOrAdd(typeof(TITarget), key => getMethodInfo(key))
...
private static MethodInfo getMethodInfo(Type type)
{
            var types = getInheritanceHierarchy(type);
...

The error message is essentially saying that the compiler guesses you want to call GetOrAdd(TKey, Func<TKey,TValue>), but that obviously needs a lambda with the key as an argument.