C＃ - 数组 - 异常错误 [英] C#- arrays - exception error

问题描述

这一行抛出IndexOutOfRangeException（索引超出了数组的边界），它在代码中的这一行指向：

This line throws IndexOutOfRangeException(index was outside the bounds of array) and it is pointed on this line in the code:

names[i] += txtName.Text + "\r\n";

只有当我停止输入名称时才会发生这种情况（比如说，在输入其中几个名字之后，点击显示名称按钮后，我会得到我输入的列表。但是当我再次继续输入名称时，我收到异常错误？



因此，如果我继续输入高达100的名字而不在中间点击节目名称，则没有错误。我应该能够在击中节目名称之后连续添加名称因为它不超过100个名字。



任何想法为什么？

This happens only if I stop entering names(lets say after entering few of them and after hitting show names button, I get the list that I entered. But when I continue entering name again, I get the exception error?

So if I continue entering names upto 100 without hitting show names in the middle, no error. I should be able to contunie add names after hitting the show names as long as it is not beyond 100 names.

Any ideas why?

<pre lang="C#">namespace Arrays
{
    public partial class frmMain : Form
    {
        public frmMain()
        {
            InitializeComponent();
        }



        //initialize the Array
        string[] names = new string[100];

        int i = 0;


        //Enter  Names up to 100 and store them in array
        private void btnEnterName_Click(object sender, EventArgs e)
        {

            names[i] += txtName.Text + "\r\n";

            txtName.Clear();

        }



        //Display stored Names in Array using foreach loop in multiline textbox
        private void btnShowNames_Click(object sender, EventArgs e)
        {
            foreach (var item in names)
            {

                txtNames.Text += names[i] + "\r\n";

                i++;


            }

        }

    }
}

我的尝试：



在指向错误的行之后尝试了i ++但没有成功。

What I have tried:

tried i++ after the line where error is pointed but no success.

推荐答案

你遇到变量i的问题：首先你要存储每个txtName .Text在同一个数组项（名称[0] - 这不是你想要的但它不是错误的来源）然后你增加i（在btnshowNames中）超出数组的大小（= 100）之前继续btnEntername，然后我太大（100）你得到错误。所以，不要一次使用一个变量用于多个目的。



让我们将我重命名为索引，你的代码应该是：

You're having problems with the variable i: first you're storing every txtName.Text in the same array-item (names[0] - that's not what you want but it's not the source of the error) and then you're increasing i (in btnshowNames) beyond the size of the array (= 100) before continuing with btnEntername where i is then too large (100) and you get the error. So, don't use a variable for more than one purpose at a time.

Let's rename i to index and your code should be:

private void btnEnterName_Click(object sender, EventArgs e)
{
    if (index < names.Length)
    {
        names[index++] = txtName.Text;
        txtName.Clear();
    }
    else
    {
        // array 'full'
    }
}
 
private void btnShowNames_Click(object sender, EventArgs e)
{
    txtName.Clear();
    foreach (string item in names)
    {
        txtNames.AppendText(item + Environment.NewLine);
    }
}

Peter

Peter

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