C# Visual Studio窗体上的错误"；对象引用未设置为实例等“；

所以现在这是一个使用表单的“游戏”。但是我的对象有一个错误，我不知道我为什么会这样。我有两门课：玩家和武器。我试图将player.Attack（）的结果显示为字符串，但当我单击表单上的按钮执行此操作时，会出现可爱的“对象引用未设置为对象实例”错误。我尝试了Convert.ToString（player.Attack（））；还尝试了String.Format（player.Attack（）），甚至设置了一个字符串变量来转换为字符串，但我一直遇到这个错误。我只希望方法的结果在表单标签上显示为字符串

这是玩家级

public class Player
    {
        private Form1 Login { get; set; }

       
        private Weapon sword;
        public string PlayerName { get; set; }
        public int Health { get; set; } = 36;
        public int Strength { get; set; } = 6;


        public Player(string playername, int health, int strength, Weapon s)
        {
            this.Login.UserName = playername;  //gets character name from form1 and makes it the username throughout the game. 
                                               // this.PlayerName = playername;
            this.Health = health;
            this.Strength = strength;
            this.sword = s;
        }

        public int Attack()
        {
            return sword.Attack(this.Strength);
        }

这是武器级

public class Weapon
    {
        public string Name { get; set; } = "Hel Fire";
        public int AtkDmg { get; set; } = 4;

        public Weapon(string name, int attack)
        {
            this.Name = name;
            this.AtkDmg = attack;

        }

        //Attack function that will take users STR and Sword Strength
        public int Attack(int strength)
        {
            int result = strength + this.AtkDmg; // AtkDmg is the weapons Strength
            return result;
        }

这是按钮单击对象所在的窗体

 private void AtkSword_Click(object sender, EventArgs e)
        {
            
            int GoblinHealth = 36;
            int GoblinAttack = 2;

            

            if (GoblinHealth != 0)
            {
               GoblinHealth -= player.Attack();
                player.Health -= GoblinAttack;
                
            }
            //below should display text and results from attack

      

  ResultsLabel.Text = Format.ToString("{0} Attacks the goblin. The goblin is at {1} HP. \n {2} is at {3} HP", player.PlayerName, GoblinHealth, player.PlayerName, player.Health);
            }

---

我认为问题在于：

ResultsLabel.Text = Format.ToString("{0} Attacks the goblin. The goblin is at {1} HP. \n {2} is at {3} HP", **player.PlayerName**, GoblinHealth, **player.PlayerName**, player.Health);

您正在设置变量this.Login.UserName，而不是Player.Playername。 稍后您尝试访问它，但它不存在。 您应该设置：

public Player(string playername, int health, int strength, Weapon s)
{
     this.Playername = playername //here
     this.Health = health;
     this.Strength = strength;
     this.sword = s;
}

或者使用登录用户名

ResultsLabel.Text = Format.ToString("{0} Attacks the goblin. The goblin is at {1} HP. \n {2} is at {3} HP", this.Login.UserName, GoblinHealth, this.Login.UserName, player.Health);

---

您是否将按钮点击选项中的

player

变量分配给玩家，以及玩家类中的

swool

变量？你在哪几行出错？你调试代码了吗？您是否检查了

player

是否为空？@ChetanRanpariya player不显示为空。我确实在这里调试了它，这是我得到的错误：System.NullReferenceException HResult=0x80004003 Message=Object reference未设置为对象的实例。Source=DungeonCrawler2 StackTrace:at DungeonCrawler2.Encounter1.AtkSword_Click（objectsender，EventArgs e）@ChiliPenguin我在表单中指定玩家为公共玩家。但是我没有在AtkSword_点击按钮下做，如果我应该在那里做的话？它还说第34行我得到了我的player.Attack（）所在的错误。调试你的代码。跨过它。如果你不知道怎么做或者觉得很无聊，在你弄明白之前不要再写一行代码，这很容易做到。我有这个.Login.Username，因为我的第一个表单叫做“Login”，我从那里获取用户输入并将其分配给playername。