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.| 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
outputBlock.Text &= output.ToString() & vbCrLf
' This code produces the following output:
'
' 5
' 12
' 6
' 5
' 6
' 9
' 5
' 10
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