CODEWITHSUNDEEP
c#inheritanceunity-game-engine
user2229618
user2229618

Reputation: 125

Creating a static variable for each child of a base class and getting it

I have an abstract manager class 'ManagerBase' which I want to derive and have multiple children from it that all have static references.

public abstract class ManagerBase<T> : MonoBehaviour {

public static T SharedInstance = default(T);
static bool _sharedInstanceSet = false;

/// <summary>
/// Awake this instance, assigning the shared instance. Important this awake function gets called for each derived class
/// </summary>
protected virtual void Awake() {

    if (_sharedInstanceSet != false) {

        if (BaseManagerVars.ShouldOverwritePrevious == true) {
            Toolbox.GetTools.DestroyObject(SharedInstance.gameObject); //ERROR T does not contain definition of 'gameObject' (FYI is a variable in MonoBehaviour)
        }

        else {

            Toolbox.GetTools.DestroyObject(this.gameObject);
            Debug.Log("Duplicate manager " + this.gameObject.name + " will be deleted");
            return;
        }
    }
    SharedInstance = this;   //ERROR Cannot convert type ManagerBase<T> to T
    _sharedInstanceSet = true;
}

Like so

public class EventMessageManager : ManagerBase<EventMessageManager>  {

}

Ideally I would like to be able to access the shared instance of 'EventMessageManager' by using the inherited variable 'SharedInstance'

like 

EventMessageManager.SharedInstance.whatever();

How might I go about getting this functionality? You can see I have commented in the compile errors to the base manager class.

I was originally using a static variable in the 'MangerBase' like so

public static ManagerBase<T> SharedInstance

But to get the static references of children was too long and not as neat looking

EventMessageManager manager = EventMessageManager.SharedInstance as EventMessageManager;

Thanks in advance

Upvotes: 3

Views: 1028

Answers (2)

hcb
hcb

Reputation: 8367

You can create a method getSharedInstance() which returns the shared instance of the type from a dictionary, the problem is that it need a constructor or static init method. like this:

private static Dictionary<Type, object> SharedInstances;

public static init()
{
     if (!SharedInstances.ContainsKey(T.getType()))
     {
           SharedInstances.Add(T.getType(), default(T));
     }
}

public static T getSharedInstance()
{
     return (T)SharedInstances[T.getType()];
}

Upvotes: 0

decPL
decPL

Reputation: 5402

I'm not sure exactly why you want to do such a pattern (some additional info might help), but the following should work:

public abstract class ManagerBase<T> : MonoBehaviour where T : ManagerBase<T>

and

SharedInstance = this as T;

Upvotes: 2

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