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Enumerable.ToList(Of TSource) Method

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

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

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

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.

ExceptionCondition
ArgumentNullException

source is Nothing.

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).

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.


      ' 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
      outputBlock.Text &= output.ToString() & vbCrLf

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



Windows Phone OS

Supported in: 8.1, 8.0, 7.1, 7.0

Windows Phone

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