Question

尝试循环浏览我的角色，但是当我在最后一个角色点击下一个时，它会中断。 visual studio给出的响应是：ArgumentOutOfRangeException未处理并且引用了我的“playerCharacter pc = player [currentPlayerIndex];”

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace RPGExample
{
    public partial class Form1 : Form
    {

        private List<PlayerCharacter> player;

        int currentPlayerIndex = 0;

        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            // set up an empty list
            player = new List<PlayerCharacter>();


            // add a couple of players
            player.Add(new PlayerCharacter("Attila"));

            player.Add(new PlayerCharacter("Boromir"));

            // create some weapons (could be in a list too)
            Weapon sword = new Weapon("Broadsword",40,5);

            Weapon leatherShield = new Weapon("Leather Shield",2,35);

            Weapon woodenStaff = new Weapon("Wooden Staff",30,10);

            // and some food
            Food bread = new Food("Bread", 15);

            // because Weapons and food inherit from CollectableObject
            // a player can carry either (polymorphism)

            // equip the players
            player[0].Add(sword);
            player[0].Add(leatherShield);

            player[1].Add(woodenStaff);

            player[1].Add(bread);


            //  display the player we are viewing
            DisplayPlayer(currentPlayerIndex);

        }


        // display info about a player by calling objects to string function
        public void DisplayPlayer(int playerIndex)
        {
            // we number from 1 for the user
            // try removing the brackets around playerIndex + 1 !!!
            lblPlayerInfo.Text = "Player " + (playerIndex + 1);

            PlayerCharacter pc = player[currentPlayerIndex];
            txtPlayers.Text = pc.ToString();
        }

        private void btnPrevious_Click(object sender, EventArgs e)
        {
            if (currentPlayerIndex > 0)
            {
                currentPlayerIndex--;
                DisplayPlayer(currentPlayerIndex);
            }
        }

        private void btnNext_Click(object sender, EventArgs e)
        {
            if (currentPlayerIndex < player.Count)
            {
                currentPlayerIndex++;
                DisplayPlayer(currentPlayerIndex);
            }
        }

    }
}

Answer 1

您应该在递增/递减currentPlayerIndex之前使用DisplayPlayer，或者通过与等式（＆lt; =）进行比较来替换严格比较（＆lt;）。）

    private void btnPrevious_Click(object sender, EventArgs e)
    {
        if (currentPlayerIndex >= 0)
        {
            currentPlayerIndex--;
            DisplayPlayer(currentPlayerIndex);
        }
    }

    private void btnNext_Click(object sender, EventArgs e)
    {
        if (currentPlayerIndex < player.Count)
        {
            currentPlayerIndex++;
            DisplayPlayer(currentPlayerIndex);
        }
    }

VS打破一次列表超过2（1）而不是循环回到0

1 个答案: