Coroutine method doesn't get called after subscribing to Func event

Question

In Unity, I have the following script which contains a func that takes in a Vector2 as an argument and returns IEnumerator

using System;
using System.Collections;
using UnityEngine;

public class Weapon : MonoBehaviour
{
    public static event Func<Vector2, IEnumerator> OnFire;

    private void OnMouseDown()
    {
        Fire();
    }

    private void Fire()
    {
        Vector2 mousePosition = new Vector2(Camera.main.ScreenToWorldPoint(Input.mousePosition).x, Camera.main.ScreenToWorldPoint(Input.mousePosition).y);

        if (OnFire != null)
        {
            OnFire.Invoke(mousePosition);
        }
    }
}

In my other script, I have a Coroutine that subscribes to that method

using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Bullet : MonoBehaviour
{

    private void Start()
    {
        Weapon.OnFire += ShootAt;
    }

    private IEnumerator ShootAt(Vector2 target)
    {
        yield return new WaitForSeconds(.5f);
        print("Shot at " + target);
    }

    private void OnDestroy()
    {
        Weapon.OnFire -= ShootAt;
    }

}

But the ShootAt method in my Bullet script never gets called. It's as if it's not even subscribing to the event. I don't have any compile errors.

Answer 1

The ShootAt function you are subscribing to the OnFire event is not a normal function. It's a coroutine function which requires the use of StartCoroutine to call it. Put your OnFire.Invoke call inside the StartCoroutine function and it should work.

Replace

OnFire.Invoke(mousePosition);

with

StartCoroutine(OnFire.Invoke(mousePosition));