c# event Action 判斷事件列表中是否存在這個委托

using UnityEngine;
using System.Collections;
using System;

public class eventTest : MonoBehaviour 
{

    private event Action<uint> onClick;
    private uint i = 0;
    // Use this for initialization
    void Start () 
    {
        onClick += OnClick;
        onClick += OnClick;
        onClick += OnClick;
        onClick += OnClick;
        onClick += OnClick;
        onClick += OnClick;
        onClick += OnClick2;
    }
    
    // Update is called once per frame
    void Update ()
    {
        if (Input.GetMouseButtonUp(0))
        {
            Delegate[] list = onClick.GetInvocationList();

            Debug.Log("存在在" + Array.IndexOf(list, (Action<uint>)OnClick2));
           
            //for (int i = 0; i < list.Length; i++ )
            //{
            //    if(list[i].Equals((Action<uint>)OnClick))
            //    {

            //    }
            //}
        }
    }

    private void OnClick(uint i)
    {
        Debug.Log(i);
        i++;
    }

    private void OnClick2(uint i)
    {

    }
}

不存在輸出為-1，存在輸出為大於0的index