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Enumerable.ToList<TSource> Method

Creates a List<T> from an IEnumerable<T>.

Namespace:  System.Linq
Assembly:  System.Core (in System.Core.dll)

public static List<TSource> ToList<TSource>(
	this IEnumerable<TSource> source
)

Type Parameters

TSource

The type of the elements of source.

Parameters

source
Type: System.Collections.Generic.IEnumerable<TSource>
The IEnumerable<T> to create a List<T> from.

Return Value

Type: System.Collections.Generic.List<TSource>
A List<T> that contains elements from the input sequence.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type IEnumerable<TSource>. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).

ExceptionCondition
ArgumentNullException

source is null.

The ToList<TSource>(IEnumerable<TSource>) method forces immediate query evaluation and returns a List<T> that contains the query results. You can append this method to your query in order to obtain a cached copy of the query results.

ToArray<TSource> has similar behavior but returns an array instead of a List<T>.

The following code example demonstrates how to use ToList<TSource> to force immediate query evaluation and return a List<T> that contains the query results.


            string[] fruits = { "apple", "passionfruit", "banana", "mango", 
                                  "orange", "blueberry", "grape", "strawberry" };

            List<int> lengths = fruits.Select(fruit => fruit.Length).ToList();

            foreach (int length in lengths)
            {
                Console.WriteLine(length);
            }

            /*
             This code produces the following output:

             5
             12
             6
             5
             6
             9
             5
             10
            */



.NET Framework

Supported in: 4, 3.5

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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