How do I take a lambda expression as a parameter that returns a method?

Question

I want to be able to do this:

var test = SomeMethod(s => s.SomeMethod);

I can make it work with properties by making the method signature look like this:

SomeMethod<TProperty>(Expression<Func<T, TProperty>> expression)

How can I make it work with methods? I know this is simple, I'm just missing something small.

Answer 1

Something like this?

    public SimpleCommand( Predicate<object> canExecuteDelegate, Action<object> executeDelegate )
    {
        CanExecuteDelegate = canExecuteDelegate;
        ExecuteDelegate = executeDelegate;
    }

You will need to specify the function signature using Predicate or Action.

Answer 2

Take a look here:

How to pass a function as a parameter in C#?

Pass Method as Parameter using C#

Answer 3

class Program
    {
        public class Test
        {
            public bool SomeMethod(string test)
            {
                return true;
            }
        }

        static void Main(string[] args)
        {

            Test testObj = new Test();


            Func<string, bool> rule1 = AddRule(testObj, x => x.SomeMethod);

            bool rsult = rule1("ttt");

        }

        static Func<string, bool> AddRule<T>( T obj, Func<T,Func<string, bool>> func)
        {
            return func(obj);
        }


}

Answer 4

Is something like this what you're looking for?

DoSomethingWithAction<T>(Func<T, Action> actionRetriever) { }
DoSomethingWithFunction<T, TResult>(Func<T, Func<TResult>> functionRetriever) { }

You would call these like:

DoSomethingWithAction<ObjectWithMethod>(obj => obj.Method);
DoSomethingWithFunction<ObjectWithProperty>(obj => obj.Property);

Answer 5

I think, there's no way of doing this without specifying the method signature: Just think of overloaded methods:

void SomeMethod() { }
int SomeMethod(int a, int b) { return 0; }

// ...

var test = TestMethod(s => s.SomeMethod);

How would the compiler possibly know, which of the methods you want to test?