我们如何处理索引超出范围的异常 [英] how can we handle index out of range exception

问题描述

变量"can_Count"的值为5，但此代码仍会导致超出范围的异常.此代码的目的是创建许多动态按钮(它不应该创建can_Count的按钮)变量成立.)我找不到这段代码有什么问题.有人可以帮我吗?

the variable "can_Count" is getting the value of 5.but still this code causes for an out of range exception.The purpose of this code is to create a number of dynamic buttons(it should create no of buttons which the can_Count variable holds.) I can''t find what is wrong with this code.can anyone help me?

public static int can_Count = 0;
//there is a function which count the no of rows in a table n return it to can_Count

static int a_size = (can_Count + 1);
public Button[] bu1 = new Button[a_size];

private void Form9_Load(object sender, EventArgs e)
{
 x = 40;
 for (int i = 1; i <=can_Count; i++)
 {
  bu1[i] = new Button();
  bu1[i].Name = "BI" + i;
  bu1[i].Text = "1";
  bu1[i].Location = new Point(20, x);
  x = x + 75;
  bu1[i].Click += new EventHandler(button1_Click);
 }
this.Controls.AddRange(bu1);
}

推荐答案

正如Simmons先生所说，这是您错的地方:

As mr Simmons stated, this is where you''re wrong:

for (int i = 1; i <=can_Count; i++)

应该是:

It should be:

for (int i = 1; i < can_count; i++)

您正在使系统超出范围异常，因为您尝试访问的数组中没有数据.

例如，假设您的数组的计数为4.数组中的第一个元素位于array [0]中，最后一个位于array [3]中. array [4]不存在，如果您尝试访问其中的信息，则会使系统超出范围异常.
0,1,2,3实际上是数组中的4个元素

当您为i< = can_Count循环时，应为i< can_Count.

You''re getting the system out of range exception because you''re trying to access data in the array where there is none.

Example, say your array has a count of 4. The first element in the array is located in array[0] and the last in array[3]. array[4] does not exist and if you''re trying to access information in it, you will get the system out of range exception.
0,1,2,3 is actually 4 elements in the array

This happens when your looping for i <=can_Count, it should be i <can_Count.

在.Net中索引从0开始，因此您需要执行此操作(假设已初始化为适当的尺寸):

Indexes are 0-based in .Net, so you need to do this (assuming bu1 is already initialized to the proper dimensions):

for (int i = 1; i < can_count; i++)
{
    ....
}

编辑

我会这样:

EDIT

I would do it this way:

for (int i = 1; i < bu1.Length; i++)
{
    Button button = new Button() {
                                   .Name     = string.Format("BI{0}", i),
                                   .Text     = i.ToString(),
                                   .Location = new Point(20, x)
                                 }
    x += 75;
    bu1[i] = button;
}

并请注意，在您的版本中，您正在尝试向字符串添加整数值(在此设置按钮的Name属性).这也会引发范围异常.

And notice that in your version, you''re trying to add an integer value to a string (where you set the Name property of the button). That will also throw a range exception.

我不确定我是否正确，但是此代码创建了5个按钮，而没有生成任何异常:

I''am not sure if i get you right, but this code creates 5 buttons without any exception generated:

public static int can_Count = 5;
       //there is a function which count the no of rows in a table n return it to can_Count

       static int a_size = (can_Count + 1);
       public Button[] bu1 = new Button[a_size];



       private void button1_Click(object sender, EventArgs e)
       {
           int x = 40;
           for (int i = 1; i <= can_Count; i++)
           {
               bu1[i] = new Button();
               bu1[i].Name = "BI" + i;
               bu1[i].Text = "1";
               bu1[i].Location = new Point(20, x);
               x = x + 75;

           }
           this.Controls.AddRange(bu1);

       }

这篇关于我们如何处理索引超出范围的异常的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！