c#查找列表指定元素的索引

Given a Collection<T> of Integer and we have to insert an element at given index.

给定Integer的Collection <T>，我们必须在给定的索引处插入一个元素。

To insert an element in Collection<T>, we use Insert() method, it accepts two parameters index and item, where index is an integer type and item is of T type i.e. the type of the Collection<T>.

要在Collection <T>中插入元素，我们使用Insert()方法 ，它接受两个参数index和item ，其中index是整数类型，而item是T类型，即Collection <T>的类型。

Syntax:

句法：

    public void Insert (int index, T item);

Note: Insert() method may return exception (ArgumentOutOfRangeException), if index is either less than 0 or greater than the count.

注意：如果index小于0或大于count，则Insert()方法可能会返回异常( ArgumentOutOfRangeException )。

用C＃代码在Collection <T>中插入元素 (C# code to insert an element in the Collection<T>)

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
class IncludeHelp
{public static void Main()
{// declaring a collection of integers
Collection<int> iColl = new Collection<int>();
// adding elements to the collection
iColl.Add(100);
iColl.Add(200);
iColl.Add(300);
iColl.Add(400);
// displaying total number of elements
Console.WriteLine("Total number of elements: " + iColl.Count);
// displaying all elements
foreach (int ele in iColl)
{Console.WriteLine(ele);
}
// now inserting 900 at 3rd index
iColl.Insert(3, 900);
// displaying total number of elements
Console.WriteLine("Total number of elements: " + iColl.Count);
// displaying all elements
foreach (int ele in iColl)
{Console.WriteLine(ele);
}
}
}

Output

输出量

Total number of elements: 4
100
200
300
400
Total number of elements: 5
100
200
300
900
400

Displaying exception

显示异常

Here, we will insert an element at -1 index that will generate "ArgumentOutOfRangeException" exception.

在这里，我们将在-1索引处插入一个元素，该元素将生成“ ArgumentOutOfRangeException”异常。

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
class IncludeHelp
{public static void Main()
{// declaring a collection of integers
Collection<int> iColl = new Collection<int>();
// adding elements to the collection
iColl.Add(100);
iColl.Add(200);
iColl.Add(300);
iColl.Add(400);
// displaying total number of elements
Console.WriteLine("Total number of elements: " + iColl.Count);
// displaying all elements
foreach (int ele in iColl)
{Console.WriteLine(ele);
}
// now inserting 900 at -1 index
// that will generate exception
iColl.Insert(-1, 900);
// displaying total number of elements
Console.WriteLine("Total number of elements: " + iColl.Count);
// displaying all elements
foreach (int ele in iColl)
{Console.WriteLine(ele);
}
}
}

Output

输出量

Total number of elements: 4
100
200
300
400
Unhandled Exception:
System.ArgumentOutOfRangeException: Index must be within the bounds of the List.
Parameter name: index
at System.ThrowHelper.ThrowArgumentOutOfRangeException
(System.ExceptionArgument argument, System.ExceptionResource resource) [0x00029]
in <65984520577646ec9044386ec4a7b3dd>:0
at System.Collections.ObjectModel.Collection`1[T].Insert (System.Int32 index, T item)
[0x00026] in <65984520577646ec9044386ec4a7b3dd>:0
at IncludeHelp.Main () [0x0007f] in <d658237a48934373b441d64c47cad823>:0
[ERROR] FATAL UNHANDLED EXCEPTION: System.ArgumentOutOfRangeException:
Index must be within the bounds of the List.
Parameter name: index
at System.ThrowHelper.ThrowArgumentOutOfRangeException
(System.ExceptionArgument argument, System.ExceptionResource resource) [0x00029]
in <65984520577646ec9044386ec4a7b3dd>:0
at System.Collections.ObjectModel.Collection`1[T].Insert (System.Int32 index, T item)
[0x00026]
in <65984520577646ec9044386ec4a7b3dd>:0
at IncludeHelp.Main () [0x0007f] in <d658237a48934373b441d64c47cad823>:0

翻译自: https://www.includehelp.com/dot-net/inserting-an-element-at-specified-index-in-a-collection-t-in-csharp.aspx

c#查找列表指定元素的索引