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c# - Visual Studio Form 上的错误“对象引用未设置为实例等”

问题描述

所以这是一个使用表格的“游戏”。但是我的对象出现错误，我不确定我到底是为什么。我有以下 2 个课程：玩家和武器。我试图让 player.Attack() 的结果显示为字符串，但是当我单击表单上的按钮时，它给了我可爱的“对象引用未设置为对象的实例”错误。我试过 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，但我一直收到这个错误。我只希望方法的结果在我的表单标签上显示为字符串。

这是 PLAYER 类

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);
        }

这是武器类

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 button_click 对象所在的表单。

 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);
            }

标签： c#formsmethodsoverriding

解决方案

我认为问题出在这里：

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。稍后您尝试访问它并且它不存在。你应该设置：

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);

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