索引数组错误

Question

嗨，我遇到了一个问题，我一直收到这个错误：

  

索引超出了数组的范围。

var d = File.ReadAllLines(@"studentsFile.txt");
var t = d.Where(g => g.Contains("Student Name"));
string[] splited;
foreach (var item in t)
{
    splited = item.Split(new string[] { "Student Name:" }, StringSplitOptions.None);
    cbListStudents.Items.Add(splited[1]);
}

以上工作完美，但下面的代码不是：

var cour = File.ReadAllLines(@"CourseFile.txt");
var courFind = cour.Where(g => g.Contains("Course"));
string[] splited2;
foreach (var item in courFind)
{
    splited2 = item.Split(new string[] { "Course:" }, StringSplitOptions.None);
    cbListCourses.Items.Add(splited2[1]);//here is where the issues starts
}

Answer 1

至少你应该检查数组长度：

var cour = File.ReadAllLines(@"CourseFile.txt");
var courFind = cour.Where(g => g.Contains("Course"));
string[] splited2;
foreach (var item in courFind)
{
  splited2 = item.Split(new string[] { "Course:" }, StringSplitOptions.None);
  if(splited2.Length >= 2)
    cbListCourses.Items.Add(splited2[1]);//here is where the issues starts
}

Answer 2

foreach (var item in courFind)
{
   splited2 = item.Split(new string[] { "Course:" }, StringSplitOptions.None);
   cbListCourses.Items.Add(splited2[0]); // Array Index starts with 0
}

Answer 3

您必须检查数组的Length（如果该文件有，例如<​​em>空行，该怎么办？）

var data = File
  .ReadLines(@"CourseFile.txt")
  .Select(line => new string[] { "Course:" }, StringSplitOptions.None)
  .Where(items => item.Length >= 2) // Check array's Length
  .Select(items => items[1])        // Now it's safe to address the 2nd item  
  .ToArray();                       // ComboBox.Items.AddRange wants array

cbListCourses.Items.AddRange(data);

Answer 4

该行文件中可能不包含任何冒号（:)。

你应该检查好像

var courFind = cour.Where(g => g.Contains("Course:"));

而不是之前的。

测试用例：

1. 带有空内容
的文件
2. 内容 - ＆gt;的课程：
3. 内容 - ＆gt; 课程（与您面临的错误相同）

代码：

 var cbListStudents = new List<String> ();
 var cbListCourses = new List<String> ();

 var d = File.ReadAllLines (@"res/TestFile.txt");
 var t = d.Where (g => g.Contains ("Student Name"));
 string[] splited;
 foreach (var item in t) {
    splited = item.Split (new string[] { "Student Name:" }, StringSplitOptions.None);
    cbListStudents.Add (splited[1]);
 }

 var cour = File.ReadAllLines (@"res/TestFile2.txt");
 var courFind = cour.Where (g => g.Contains ("Course"));
 string[] splited2;
 foreach (var item in courFind) {
    splited2 = item.Split (new string[] { "Course:" }, StringSplitOptions.None);
    cbListCourses.Add (splited2[1]); //here is where the issues starts
 }