Enumerable.ToList(Of TSource) Method
Creates a List(Of T) from an IEnumerable(Of T).
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. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).| Exception | Condition |
|---|---|
| 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
MsgBox(output.ToString())
' This code produces the following output:
'
' 5
' 12
' 6
' 5
' 6
' 9
' 5
' 10
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.