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List<T>.InsertRange(Int32, IEnumerable<T>) Method

Definition

Namespace:
System.Collections.Generic
Assemblies:
mscorlib.dll, System.Collections.dll
Assemblies:
netstandard.dll, System.Collections.dll
Assembly:
System.Collections.dll
Assembly:
mscorlib.dll
Assembly:
netstandard.dll
Source:
List.cs
Source:
List.cs
Source:
List.cs
Source:
List.cs

Inserts the elements of a collection into the List<T> at the specified index.

public:
 void InsertRange(int index, System::Collections::Generic::IEnumerable<T> ^ collection);
public void InsertRange(int index, System.Collections.Generic.IEnumerable<T> collection);
member this.InsertRange : int * seq<'T> -> unit
Public Sub InsertRange (index As Integer, collection As IEnumerable(Of T))

Parameters

index
Int32

The zero-based index at which the new elements should be inserted.

collection
IEnumerable<T>

The collection whose elements should be inserted into the List<T>. The collection itself cannot be null, but it can contain elements that are null, if type T is a reference type.

Exceptions

ArgumentNullException

collection is null.

ArgumentOutOfRangeException

index is less than 0.

-or-

index is greater than Count.

Examples

The following example demonstrates InsertRange method and various other methods of the List<T> class that act on ranges. After the list has been created and populated with the names of several peaceful plant-eating dinosaurs, the InsertRange method is used to insert an array of three ferocious meat-eating dinosaurs into the list, beginning at index location 3.

using System;
using System.Collections.Generic;

string[] input = { "Apple",
                   "Banana",
                   "Orange" };

List<string> fruits = new List<string>(input);

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

foreach (string fruit in fruits)
{
    Console.WriteLine(fruit);
}

Console.WriteLine("\nAddRange(fruits)");
fruits.AddRange(fruits);

Console.WriteLine();
foreach (string fruit in fruits)
{
    Console.WriteLine(fruit);
}

Console.WriteLine("\nRemoveRange(2, 2)");
fruits.RemoveRange(2, 2);

Console.WriteLine();
foreach (string fruit in fruits)
{
    Console.WriteLine(fruit);
}

input = new string[] { "Mango",
                       "Pineapple",
                       "Watermelon" };

Console.WriteLine("\nInsertRange(3, input)");
fruits.InsertRange(3, input);

Console.WriteLine();
foreach (string fruit in fruits)
{
    Console.WriteLine(fruit);
}

Console.WriteLine("\noutput = fruits.GetRange(2, 3).ToArray()");
string[] output = fruits.GetRange(2, 3).ToArray();

Console.WriteLine();
foreach (string fruit in output)
{
    Console.WriteLine(fruit);
}

/*
    This code example produces the following output:

    Capacity: 3

    Apple
    Banana
    Orange

    AddRange(fruits)

    Apple
    Banana
    Orange
    Apple
    Banana
    Orange

    RemoveRange(2, 2)

    Apple
    Banana
    Banana
    Orange

    InsertRange(3, input)

    Apple
    Banana
    Banana
    Mango
    Pineapple
    Watermelon
    Orange

    output = fruits.GetRange(2, 3).ToArray()

    Banana
    Mango
    Pineapple
*/

Imports System.Collections.Generic

Partial Public Class Program
    Public Shared Sub ShowFruits()

        Dim input() As String = { "Apple", _
                                  "Banana", _
                                  "Orange" }

        Dim fruits As New List(Of String)(input)

        Console.WriteLine(vbLf & "Capacity: {0}", fruits.Capacity)
        Console.WriteLine()

        For Each fruit As String In fruits
            Console.WriteLine(fruit)
        Next

        Console.WriteLine(vbLf & "AddRange(fruits)")
        fruits.AddRange(fruits)

        Console.WriteLine()
        For Each fruit As String In fruits
            Console.WriteLine(fruit)
        Next

        Console.WriteLine(vbLf & "RemoveRange(2, 2)")
        fruits.RemoveRange(2, 2)

        Console.WriteLine()
        For Each fruit As String In fruits
            Console.WriteLine(fruit)
        Next

        input = New String() { "Mango", _
                               "Pineapple", _
                               "Watermelon" }

        Console.WriteLine(vbLf & "InsertRange(3, input)")
        fruits.InsertRange(3, input)

        Console.WriteLine()
        For Each fruit As String In fruits
            Console.WriteLine(fruit)
        Next

        Console.WriteLine(vbLf & "output = fruits.GetRange(2, 3).ToArray")
        Dim output() As String = fruits.GetRange(2, 3).ToArray()

        Console.WriteLine()
        For Each fruit As String In output
            Console.WriteLine(fruit)
        Next

    End Sub
End Class

' This code example produces the following output:
'
' Capacity: 3
'
' Apple
' Banana
' Orange
'
' AddRange(fruits)
'
' Apple
' Banana
' Orange
' Apple
' Banana
' Orange
'
' RemoveRange(2, 2)
'
' Apple
' Banana
' Banana
' Orange
'
' InsertRange(3, input)
'
' Apple
' Banana
' Banana
' Mango
' Pineapple
' Watermelon
' Orange
'
' output = fruits.GetRange(2, 3).ToArray
'
' Banana
' Mango
' Pineapple

Remarks

List<T> accepts null as a valid value for reference types and allows duplicate elements.

If the new Count (the current Count plus the size of the collection) will be greater than Capacity, the capacity of the List<T> is increased by automatically reallocating the internal array to accommodate the new elements, and the existing elements are copied to the new array before the new elements are added.

If index is equal to Count, the elements are added to the end of List<T>.

The order of the elements in the collection is preserved in the List<T>.

This method is an O(n * m) operation, where n is the number of elements to be added and m is Count.

Applies to

See also