如何存储使用 2 个键查找值的数据对象

Question

I need to tie 3 types of things together:

1. an enum (state)
2. another enum (type of function)
3. a function reference.

The context of my project is that I have a video game state machine that exists in a single class. I have several switch statements that I am trying to replace. Each state has a set of functions associated with it, such as Enter() and Exit().

In English, I want to say, "for ___ state, call ___ type of function" and then it calls the actual function. For example, I'd like to do something like this:

Lookup [states.attacking] [stateFunctions.enter];

where this would return a call to "void Attacking_Enter()"

Answer 1

You could use a

Dictionary<states, Dictionary<stateFunctions, Action>> Lookup = new Dictionary<states, Dictionary<stateFunctions, Action>>();

so you can look up and execute via eg

// First Key finds the inner dictionary
// Second key finds the action in the inner dictionary
// ? makes sure you don't get NullReferenceExceptions (just in case)
// Invoke() finally executed the stored action
Lookup[states.enter][stateFunctions.attack]?.Invoke();

---

Careful while filling it: Make sure to initialize the inner Dictionary (s) before adding elements to it eg

Lookup[states.enter] = new Dictionary<stateFunctions, Action>();
Lookup[states.enter][stateFunctions.attack] = Attacking_Enter;

Or initialize them all in one go like eg

private void Initialize ()
{
    Lookup = new Dictionary<states, Dictionary<stateFunctions, Action>>
    {
        {states.enter, new Dictionary<stateFunctions, Action>
                       { 
                           {stateFunctions.attack, Attacking_Enter}, 
                           ...
                       }
        },
        ...
    }     
}

Answer 2

 var dict = Dictionary<Dictioanry<T1, T2>, T3>();

where T1, T2 and T3 are your desired data types.

Answer 3

You can try Tuple

var dict = new Dictionary<Tuple<T1, T2>, T3>();

Or Class object which implement GetHashCode if needed

var dict = new Dictionary<ClassObj, T3>();