AddRange Method

List<T>.AddRange Method (IEnumerable<T>)

 

Adds the elements of the specified collection to the end of the List<T>.

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

public void AddRange(
	IEnumerable<T> collection
)

Parameters

collection
Type: System.Collections.Generic.IEnumerable<T>

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

Exception Condition
ArgumentNullException

collection is null.

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

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 the List<T> can accommodate the new elements without increasing the Capacity, this method is an O(n) operation, where n is the number of elements to be added. If the capacity needs to be increased to accommodate the new elements, this method becomes an O(n + m) operation, where n is the number of elements to be added and m is Count.

The following example demonstrates the AddRange method and various other methods of the List<T> class that act on ranges. An array of strings is created and passed to the constructor, populating the list with the elements of the array. The AddRange method is called, with the list as its argument. The result is that the current elements of the list are added to the end of the list, duplicating all the elements.

using System;
using System.Collections.Generic;

public class Example
{
    public static void Main()
    {
        string[] input = { "Brachiosaurus", 
                           "Amargasaurus", 
                           "Mamenchisaurus" };

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

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

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

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

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

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

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

        input = new string[] { "Tyrannosaurus", 
                               "Deinonychus", 
                               "Velociraptor"};

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

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

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

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

/* This code example produces the following output:

Capacity: 3

Brachiosaurus
Amargasaurus
Mamenchisaurus

AddRange(dinosaurs)

Brachiosaurus
Amargasaurus
Mamenchisaurus
Brachiosaurus
Amargasaurus
Mamenchisaurus

RemoveRange(2, 2)

Brachiosaurus
Amargasaurus
Amargasaurus
Mamenchisaurus

InsertRange(3, input)

Brachiosaurus
Amargasaurus
Amargasaurus
Tyrannosaurus
Deinonychus
Velociraptor
Mamenchisaurus

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

Amargasaurus
Tyrannosaurus
Deinonychus
 */

Universal Windows Platform
Available since 4.5
.NET Framework
Available since 2.0
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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