Can you change an enum state with a string value?

Unity Engine
1

My problem is that I have an enum which defines what state the player is in. Everytime the enum changes it does everything I want it to however I’m having problems changing the actual enum state. The way I would like it to work is that everytime they enter a trigger, to change the enum state to the triggers tag. For example as soon as they pass the first trigger it will put them into enum state “one”. This trigger has a tag on it named “one”. I know I could get it to work a couple different ways but is there a way I could take this trigger tag as a string and change the enum state , a psuedo code example would be,

        void OnTriggerEnter2D(Collider2D collider)
    {
        string newEnum = collider.tag;
        EnumScript.Instance.Enum = newEnum;
    }

This code above obviosly doesn’t work but is there a way I can do something similiar?
I could accomplish it by changing trigger to the object itself and putting a script on each object that a trigger is on but this would require a lot of scripts and does not seem efficient for what I’m trying to do.

2

Enum values can both be assigned an integer and referenced as an integer:

//Example with implicit values.
enum Example1 {
   State1, // = 0 by default
   State2, // = 1 by default
   State3  // = 2 by default
}

//Example with explicit values.
enum Example1 {
   State1 = 1,
   State2 = 2,
   State3 = 3
}

If you must use tags, then you can name the tag as the integer value corresponding to the enum state and parse it as an integer to set the enum’s value:

public class Example : MonoBehaviour {
   public State currentState;

   void OnTriggerEnter2D(Collider2D collider) {
      int newState = int.Parse(collider.tag); //Assume the tag is named "1" or "2" or "3", etc...
      currentState = (State)newState;
   }
}

public enum State {
   State1,
   State2,
   State3
}

I find using tags for this to be a bit messy however. Another way you can go about this is to create a very basic script attached to each of the GameObjects containing the trigger colliders, which simply stores a value of the state for the player to change to when entering the collider:

public class StateAssigner : MonoBehaviour {
   public State state;
}

public class Example : MonoBehaviour {
   public State currentState;

   void OnTriggerEnter2D(Collider2D collider) {
      StateAssigner stateAssigner = collider.gameObject.GetComponent<StateAssigner>();

      if(stateAssigner != null) {
         currentState = stateAssigner.state;
      }
   }
}

public enum State {
   State1,
   State2,
   State3
}
1 Like
3

I wouldn’t really advocate doing it this way- to me, it makes more sense that you have a lookup table with a string ID that says what Enum value the given tag corresponds to.

private Dictionary<string, SomeEnum> mEnumLookup;

private Awake()
{
    mEnumLookup = new Dictionary<string SomeEnum>()
    {
        { "SomeTagA", SomeEnum.SomeEnumValueA },
        { "SomeTagB", SomeEnum.SomeEnumValueB }
    };
}

This means you can just get the enum value by doing mEnumLookup[“SomeTagA”], and you can have multiple tags pointing to the same Enum value, if and when it’s needed.

That said, you can actually do what you ask directly using:

(SomeEnum)Enum.Parse(typeof(SomeEnum), "SomeTagA");

This will check the string “SomeTagA” against the names of the Enum members, instead of the values, then hand you back the Enum value. Be very careful with this- it defeats some of the purpose of enumerations I feel, that the string name is being relied upon this way, but it’s available if you need it.

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