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List.Insert Method

.NET Framework 2.0

Other Versions

Inserts an element into the List at the specified index.

Namespace: System.Collections.Generic
Assembly: mscorlib (in mscorlib.dll)

Syntax

C++

Copy

public void Insert (
	int index,
	T item
)

Copy

public final void Insert (
	int index, 
	T item
)

JScript

Copy

public final function Insert (
	index : int, 
	item : T
)

XAML

Copy

Not applicable.

Parameters

index: The zero-based index at which item should be inserted.

item: The object to insert. The value can be a null reference (Nothing in Visual Basic) for reference types.

Exceptions

Exception type	Condition
ArgumentOutOfRangeException	index is less than 0. -or- index is greater than Count.

Exception type

Condition

ArgumentOutOfRangeException

index is less than 0.

-or-

index is greater than Count.

Remarks

List accepts a null reference (Nothing in Visual Basic) as a valid value for reference types and allows duplicate elements.

If Count already equals Capacity, the capacity of the List is increased by automatically reallocating the internal array, and the existing elements are copied to the new array before the new element is added.

If index is equal to Count, item is added to the end of List.

This method is an O(n) operation, where n is Count.

Example

The following code example demonstrates the Insert method, along with various other properties and methods of the List generic class. After the list is created, elements are added. The Insert method is used to insert an item into the middle of the list. The item inserted is a duplicate, which is later removed using the Remove method.

C++

Copy

using System;
using System.Collections.Generic;

public class Example
{
    public static void Main()
    {
        List<string> dinosaurs = new List<string>();

        Console.WriteLine("\nCapacity: {0}", dinosaurs.Capacity);

        dinosaurs.Add("Tyrannosaurus");
        dinosaurs.Add("Amargasaurus");
        dinosaurs.Add("Mamenchisaurus");
        dinosaurs.Add("Deinonychus");
        dinosaurs.Add("Compsognathus");

        Console.WriteLine();
        foreach(string dinosaur in dinosaurs)
        {
            Console.WriteLine(dinosaur);
        }

        Console.WriteLine("\nCapacity: {0}", dinosaurs.Capacity);
        Console.WriteLine("Count: {0}", dinosaurs.Count);

        Console.WriteLine("\nContains(\"Deinonychus\"): {0}",
            dinosaurs.Contains("Deinonychus"));

        Console.WriteLine("\nInsert(2, \"Compsognathus\")");
        dinosaurs.Insert(2, "Compsognathus");

        Console.WriteLine();
        foreach(string dinosaur in dinosaurs)
        {
            Console.WriteLine(dinosaur);
        }

        Console.WriteLine("\ndinosaurs[3]: {0}", dinosaurs[3]);

        Console.WriteLine("\nRemove(\"Compsognathus\")");
        dinosaurs.Remove("Compsognathus");

        Console.WriteLine();
        foreach(string dinosaur in dinosaurs)
        {
            Console.WriteLine(dinosaur);
        }

        dinosaurs.TrimExcess();
        Console.WriteLine("\nTrimExcess()");
        Console.WriteLine("Capacity: {0}", dinosaurs.Capacity);
        Console.WriteLine("Count: {0}", dinosaurs.Count);

        dinosaurs.Clear();
        Console.WriteLine("\nClear()");
        Console.WriteLine("Capacity: {0}", dinosaurs.Capacity);
        Console.WriteLine("Count: {0}", dinosaurs.Count);
    }
}

/* This code example produces the following output:

Capacity: 0

Tyrannosaurus
Amargasaurus
Mamenchisaurus
Deinonychus
Compsognathus

Capacity: 8
Count: 5

Contains("Deinonychus"): True

Insert(2, "Compsognathus")

Tyrannosaurus
Amargasaurus
Compsognathus
Mamenchisaurus
Deinonychus
Compsognathus

dinosaurs[3]: Mamenchisaurus

Remove("Compsognathus")

Tyrannosaurus
Amargasaurus
Mamenchisaurus
Deinonychus
Compsognathus

TrimExcess()
Capacity: 5
Count: 5

Clear()
Capacity: 5
Count: 0
 */

Platforms

Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

Version Information

.NET Framework

Supported in: 3.0, 2.0

.NET Compact Framework

Supported in: 2.0

XNA Framework

Supported in: 1.0

Reference

List Generic Class
List Members
System.Collections.Generic Namespace
InsertRange
List.Add Method
Remove

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