c#关于数组赋值问题

public class Player
    {
        //当前角色
        public static int current_player = 0;

        public int x = 0;
        public int y = 0;
        public int face = 1;
        //是否激活
        public int is_active = 0;
        //图像
        public Bitmap bitmap;
        public Player()
        {
            bitmap = new Bitmap(@"Grey.png");
            bitmap.SetResolution(96, 96);
        }
        public static void key_ctrl(Player[] player,KeyEventArgs e)
        {
            Player p = player[current_player];
            //切换角色
            if (e.KeyCode == Keys.Tab) { key_change_player(player); }
            //移动处理
            if (e.KeyCode == Keys.Left) { p.x = p.x - 5; p.face = 1; }
            if (e.KeyCode == Keys.A) { p.x = p.x - 5; p.face = 1; }
            if (e.KeyCode == Keys.Right) { p.x = p.x + 5; p.face = 2; }
            if (e.KeyCode == Keys.D) { p.x = p.x + 5; p.face = 2; }
        }
        public static void draw(Player[]player,Graphics g, int animation_ctrl)
        {
            Player p = player[current_player];
            Rectangle crazycoderRgl = new Rectangle(p.bitmap.Width / 7 * (animation_ctrl % 7), p.bitmap.Height / 2 * (p.face - 1), p.bitmap.Width / 7, p.bitmap.Height / 2);//定义区域
            Bitmap bitmap0 = p.bitmap.Clone(crazycoderRgl, p.bitmap.PixelFormat);//复制小图
            g.DrawImage(bitmap0, p.x, p.y, 280, 585);
        }
        //----------------------------------------------------------------
        //     切换角色
        //----------------------------------------------------------------
        public static void key_change_player(Player[] player)
        {
            for (int i = current_player + 1; i < player.Length; i++)
                if (player[i].is_active == 1)
                {
                    set_player(player, current_player, i);
                    return;
                }
            for (int i = 0; i < current_player; i++)
                if (player[i].is_active == 1)
                {
                    set_player(player, current_player, i);
                    return;
                }
        }

        public static void set_player(Player[] player, int oldindex, int newindex)
        {
            current_player = newindex;
            player[newindex].x = player[oldindex].x;
            player[newindex].y = player[oldindex].y;
            player[newindex].face = player[oldindex].face;
        }
    }

我正在边学边做游戏，学的书的是罗培羽的《手把手教你用c#制作rpg游戏》，其中这一段：Player p =player[current_player]，赋值的是另一个变量。之前明明都没问题，后来再打开一看p的赋值始终都是null，试过很多办法了就是没用，求解决办法，一目了然的那种。（实在是没办法了，智商太低了，在网上找了很多办法去试，就是不见效）

就这些线索，神来了也看不出来问题在哪