成员`System.Collections.Generic.List <baseplayer> .Count'不能用作方法或委托

Question

这是我为游戏中的某个插件编写的一些代码，如果有人能帮助的话，将不胜感激。

namespace Oxide.Plugins
{
    [Info("Fake Player Add Plugin", "NOT asmr", 0.0)]
    class FakePlayerAddPlugin : CSharpPlugin
    {
        public int MaximumFakePlayer = 50; //if server has more than x legit players, dont add fakes.
        public int PlayerFakeAdd = 43; //how many fake players to add
        public float PlayerCheckDelay = 120f; //how often to check for player changes in seconds

        void Loaded()
        {
            Puts("FakePlayerAddPlugin Loaded!");
        }

        float lasttime = 0f;

        void OnFrame(float delta)
        {
            if (lasttime + PlayerCheckDelay > Time.realtimeSinceStartup) return;

            lasttime = Time.realtimeSinceStartup;

            var pcount = BasePlayer.activePlayerList?.Count(n => n.IsValid()) ?? 0;
            var fcount = BasePlayer.activePlayerList?.Count(n => n == null) ?? 0;

            if (pcount >= MaximumFakePlayer)
            {
                RemoveFakePlayers();
                return;
            }

            if (PlayerFakeAdd > 0 && fcount != PlayerFakeAdd)
            {
                RemoveFakePlayers();
                AddFakePlayers(PlayerFakeAdd);
            }
        }

        public void RemoveFakePlayers()
        {
            BasePlayer.activePlayerList.RemoveAll(n => n == null);
        }

        public void AddFakePlayers(int amount)
        {
            for (int i = 0; i < amount; i++)
            {
                BasePlayer.activePlayerList.Add(null);
            }
        } 
    }
} 

我回想的是“成员'System.Collections.Generic.List.Count'不能用作方法或委托”。