列表索引越界

Question

我试图从组合框中检索一个值,并使用列表将其放入另一个组合框.

我成功地从列表中删除了值,并将其实现到其他列表中.但是当我这样做时,我的列表容量出现故障,并且我得到了索引超出范围的错误.

场景:

列出的信件选择:B

'左移按钮按下'

'B'已从信件列表中删除

'B'已添加到Numbers List

打印输出值

错误:"索引超出范围.必须是非负数且小于集合的大小

第66行:Console.WriteLine("Numbers:"+ numbers [i] +"\ tIteration:"+ i);

号码列表容量:8,字母列表容量:4.

编号列表:1,2,3,4,B.字母列表:A,C,D

码:

public partial class Form1 : Form
{
    public List<string> letters = new List<string>();
    public List<string> numbers = new List<string>();

    public Form1()
    {
        InitializeComponent();
    }

    private void Form1_Load(object sender, EventArgs e)
    {
        InitialiseLists();
        LoadListsIntoCombo();
    }

    public void InitialiseLists()
    {
        /*
         * Add Letter Data
         */
        letters.Add("A");
        letters.Add("B");
        letters.Add("C");
        letters.Add("D");

        /*
         * Add Number Data
         */
        numbers.Add("1");
        numbers.Add("2");
        numbers.Add("3");
        numbers.Add("4");

    }

    public void LoadListsIntoCombo()
    {

        comboLetter.DataSource = letters;
        comboNumber.DataSource = numbers;

    }

    public void PrintList()
    {
        /*
         * Print Lists To Console
         */
        for (int i = 0; i < numbers.Capacity; i++)
        {
            Console.WriteLine("NUM CAPACITY: " + numbers.Capacity);
            Console.WriteLine("Numbers: " + numbers[i] + "\tIteration: " + i);
        }

        for (int i = 0; i < letters.Capacity; i++)
        {
            Console.WriteLine("LET CAPACITY: " + letters.Capacity);
            Console.WriteLine("Letters : " + letters[i] + "\tIteration: " + i);

        }

    }


    private void cmdLeft_Click(object sender, EventArgs e)
    {

        AddLetterToNumber(GetLetter());
        RemoveLetter(GetLetter());

    }

    public void RemoveLetter(string value)
    {
        letters.Remove(value);
    }

    public void AddLetterToNumber(string value)
    {
        numbers.Add(value);
    }

    public string GetLetter()
    {
        string letter = comboLetter.SelectedItem.ToString();
        return letter;
    }

    public int GetLetterIndex()
    {
        int letterIndex = comboLetter.SelectedIndex;

        return letterIndex;
    }

    private void cmdRight_Click(object sender, EventArgs e)
    {
        PrintList();
    }

}

    }

非常感谢您提供的任何帮助.

Answer 1

使用Count属性而不是Capacity.因为第一个返回列表中包含的项目数.第二个只是说明在调整列表大小之前可以添加多少项.

public void PrintList()
{
   Console.WriteLine("Numbers count: " + numbers.Count);    
   for (int i = 0; i < numbers.Count; i++)   
       Console.WriteLine("Numbers: {0}\tIteration: {1}", numbers[i], i);       

   Console.WriteLine("Letters count: " + letters.Count);    
   for (int i = 0; i < letters.Count; i++)       
       Console.WriteLine("Letters : {0}\tIteration: {1}", letters[i], i);   
}