C# Creating an array of methods

Question

Well, been looking for this but since I cannot be more specific, Google seems out of answer, so I decided to ask here.

Anyway to create an array of methods that returns a value ?

Like

methodArray[0].Invoke();

Can I use delegate ? If so, how ?

like if i have 2 methods that needs same parameters

dobule Add(double number)
{
//code
}
double Remove(double number)
{
//code
}

what do i need to do in order to invoke them with index ( I dont want to deal with switch statement)

You will need to show your code and tell us in what way it does not work. The question/answers I linked to tell how to do it. — hatchet - done with SOverflow, Nov 30 '14 at 16:33
Action is a delegate and i can neither use it with List<> nor Action[] — user1926930, Nov 30 '14 at 16:37
There is a right way to do it, and many, many wrong ways. Without seeing your code, it's pretty hard to guess how you've done it wrong. — hatchet - done with SOverflow, Nov 30 '14 at 16:39
@user1926930: you very much *can* use delegates and `Action` objects with `List<>`. Again, show us some actual code (edit it into your question) and then maybe we can actually help you. — siride, Nov 30 '14 at 17:17
There is no need for actual code, which i don't have one.I'm just wondering how to do that. — user1926930, Nov 30 '14 at 19:19

score 3 · Accepted Answer · edited May 23 '17 at 12:14

3

You can create an array of Funcs. However, this is limited to methods that all have the same signature (return type and number and type of parameters).

If you have several methods that don't take any parameters you can use it like this:

var methods = new List<Func<T>>();

where T is the lowest common object in the return value, which might just be object.

var methods = new List<Func<object>>();

If you just want to call void methods, or aren't worried about the return type, you can use Action instead:

var methods = new List<Action>();

Either way, you can then invoke them like so:

foreach(var method in methods){
   var result = method();
   //or if you don't care about return type
   method();
}

You might also find this post useful: How do you use Func<> and Action<> when designing applications?

UPDATED The example below shows how you can use this technique with your Add and Remove method:

    public double Add(double number) { return 0;}
    public double Remove(double number) { return 0; }

    public void Example()
    {
        //Array of methods
        var methods = new Func<double, double>[]
        {
            n => Add(n),
            n => Remove(n)
        };

        //Invoking methods
        var number = 0d;
        foreach (var method in methods)
        {
            method(number);
        }
    }

edited May 23 '17 at 12:14

Community

1
1

answered Nov 30 '14 at 17:15

Philip Pittle

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Using the generic type 'System.Action' requires 1 type arguments This is the error. – user1926930 Nov 30 '14 at 19:18
Then use the non generic `Action` if you don't need to pass method parameters – Philip Pittle Nov 30 '14 at 20:22
explain more maybe ? non generic ? – user1926930 Nov 30 '14 at 20:28
http://msdn.microsoft.com/en-us/library/system.action(v=vs.110).aspx – Philip Pittle Nov 30 '14 at 20:30
if we have a method like this double Add() { //code } how can i add this to action list or create an action list ? – user1926930 Nov 30 '14 at 21:08
Does add take parameters? – Philip Pittle Nov 30 '14 at 21:13
yep, just one parameter. – user1926930 Nov 30 '14 at 21:41
and what type is this one parameter? – Philip Pittle Nov 30 '14 at 21:42
Please update your original question with the full signature for `Add` – Philip Pittle Nov 30 '14 at 21:50
Ok, did what you said. – user1926930 Nov 30 '14 at 21:58

C# Creating an array of methods

1 Answers1