C# 泛型方法

static void Main(string[] args)
{   
    Action<string> action = (string str) => {};
    var del = new Action<string>((string str) => {});
    Console.WriteLine(ActionHasDelegate(action, del)); // Output: False
    action += del;
    Console.WriteLine(ActionHasDelegate(action, del)); // Output: True

    Action<int, string> action1 = (int i, string str) => {};
    var del1 = new Action<int, string>((int i, string str) => {});
    Console.WriteLine(ActionHasDelegate(action1, del1)); // Output: False
    action1 += del1;
    Console.WriteLine(ActionHasDelegate(action1, del1)); // Output: True
}

static bool ActionHasDelegate<T>(T action, Delegate del) where T : Delegate
{
    foreach (var d in action.GetInvocationList())
    {
        if (d == del)
        {
            return true;
        }
    }
    return false;
}