Enumerable.ToList(TSource) Method (System.Linq)

ToList(TSource) Method

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.NET Framework Class Library

Enumerable..::.ToList<(Of <(TSource>)>) Method

Updated: November 2007

Creates a List<(Of <(T>)>) from an IEnumerable<(Of <(T>)>).

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

Syntax

Visual Basic (Declaration)

<ExtensionAttribute> _
Public Shared Function ToList(Of TSource) ( _
    source As IEnumerable(Of TSource) _
) As List(Of TSource)

Visual Basic (Usage)

Dim source As IEnumerable(Of TSource)
Dim returnValue As List(Of TSource)

returnValue = source.ToList()

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

Visual C++

[ExtensionAttribute]
public:
generic<typename TSource>
static List<TSource>^ ToList(
    IEnumerable<TSource>^ source
)

J# supports the use of generic APIs, but not the declaration of new ones.

JScript

JScript does not support generic types or methods.

Type Parameters

TSource: The type of the elements of source.

Parameters

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

Return Value

Type: System.Collections.Generic..::.List<(Of <(TSource>)>)

A List<(Of <(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<(Of <(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).

Exceptions

Exception	Condition
ArgumentNullException	source is nullNothingnullptra null reference (Nothing in Visual Basic).

Remarks

The ToList<(Of <(TSource>)>)(IEnumerable<(Of <(TSource>)>)) method forces immediate query evaluation and returns a List<(Of <(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<(Of <(TSource>)>) has similar behavior but returns an array instead of a List<(Of <(T>)>).

Examples

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

Visual Basic

' Create an array of strings.
Dim fruits() As String = _
    {"apple", "passionfruit", "banana", "mango", _
     "orange", "blueberry", "grape", "strawberry"}

' Project the length of each string and 
' put the length values into a List object.
Dim lengths As List(Of Integer) = _
    fruits _
    .Select(Function(fruit) fruit.Length) _
    .ToList()

' Display the results.
Dim output As New System.Text.StringBuilder
For Each length As Integer In lengths
    output.AppendLine(length)
Next
MsgBox(output.ToString())

' This code produces the following output:
'
' 5
' 12
' 6
' 5
' 6
' 9
' 5
' 10

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
*/

Platforms

Windows Vista, Windows XP SP2, Windows Server 2003, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC

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

Version Information