u/Grey-The-Skeleton

SOLUTION (u/Salt-Ad5394)

>You never initialize the dictionary! In Awake you're trying to check if _States.Empty but _States is null at this point

>Add `_States = new Dictionary<EEnemyState, EnemyScriptTemplate>();` at start of Awake before your loop. Also I think you mean `_States.Count == 0` instead of `_States.Empty` - dictionaries don't have Empty property

I've been working on an exam, and I wanted to create a script that serves as the body of a state machine, with the states themselves deriving from a template class.

I wanted to get all the components that derive from this template class, store them in a dictionary with an enum as a key, and enable/disable them to enter/exit them.

But I keep getting this error, despite the contents I'm trying to insert not being null. Is there something I am doing terribly wrong?

The error.

Here's the script:

 public class EnemyStateMachine : MonoBehaviour
 {
     [field: SerializeField] public EnemyData EnemyData { protected get; set; }

     //Ce dico contiendra tous les scripts d'états de la state machine,
     //permettant la création d'un nouvel état par l'héritage avec EnemyScriptTemplate.
     //Il suffit de le mettre sur l'ennemi, et de donner à l'état l'enum correct.
     [field: SerializeField] private Dictionary&lt;EEnemyState, EnemyScriptTemplate&gt; _States { get; set; }

     [field: SerializeField] private EEnemyState _SavedState { get; set; }

     private void Awake()
     {
         //On cherche tous les scripts suivant le template d'état,
         //et on vérifie si l'état qu'ils ont est déjà dans le dico.
         //Si oui, on passe au suivant, sinon, on le rajoute avec son étant en guise de clé.
         List&lt;EnemyScriptTemplate&gt; l_scriptList = new List&lt;EnemyScriptTemplate&gt;(GetComponentsInChildren&lt;EnemyScriptTemplate&gt;(true));
         for (int l_increment = 0; l_increment &lt; l_scriptList.Count; l_increment++)
         {
             if(l_scriptList[l_increment] != null) Debug.Log(l_scriptList[l_increment].State);
             //!THE ERROR HAPPENS ON THE NEXT LINE!
             if (_States.Empty || !_States.ContainsKey(l_scriptList[l_increment].State)) _States.Add(l_scriptList[l_increment].State, l_scriptList[l_increment]);
         }
         _SavedState = EEnemyState.NONE;
     }

     // Start is called once before the first execution of Update after the MonoBehaviour is created
     void Start()
     {
         SetStateActive(true);
     }

     // Update is called once per frame
     void Update()
     {
         if (EnemyData.State != _SavedState) NewState();
     }

     private void NewState()
     {
         SetStateActive(false);
         _SavedState = EnemyData.State;
         SetStateActive(true);
     }

     private void SetStateActive(bool p_newActive)
     {
         _States[_SavedState].enabled = p_newActive;
     }
 }

Error when trying to store a Monobehavior in a Dictionary