IEnumerable Interface
Exposes the enumerator, which supports a simple iteration over a non-generic collection.
Assembly: mscorlib (in mscorlib.dll)
The IEnumerable type exposes the following members.
| Name | Description | |
|---|---|---|
![]() | AsParallel | Enables parallelization of a query. (Defined by ParallelEnumerable.) |
![]() ![]() | AsQueryable | Converts an IEnumerable to an IQueryable. (Defined by Queryable.) |
![]() ![]() ![]() | Cast(Of TResult) | Casts the elements of an IEnumerable to the specified type. (Defined by Enumerable.) |
![]() ![]() ![]() | OfType(Of TResult) | Filters the elements of an IEnumerable based on a specified type. (Defined by Enumerable.) |
For the generic version of this interface see System.Collections.Generic.IEnumerable(Of T).
Notes to ImplementersIEnumerable must be implemented to support the foreach semantics of Microsoft Visual Basic. COM classes that allow enumerators also implement this interface.
The following code example demonstrates the implementation of the IEnumerable and IEnumerator interfaces for a custom collection. In this example, members of these interfaces are not explicitly called, but they are implemented to support the use of foreach (For Each in Visual Basic) to iterate through the collection.
Imports System Imports System.Collections Public Class Person Public Sub New(ByVal fName As String, ByVal lName As String) Me.firstName = fName Me.lastName = lName End Sub Public firstName As String Public lastName As String End Class Public Class People Implements IEnumerable Private _people() As Person Public Sub New(ByVal pArray() As Person) _people = New Person(pArray.Length - 1) {} Dim i As Integer For i = 0 To pArray.Length - 1 _people(i) = pArray(i) Next i End Sub Public Function GetEnumerator() As IEnumerator _ Implements IEnumerable.GetEnumerator Return New PeopleEnum(_people) End Function End Class Public Class PeopleEnum Implements IEnumerator Public _people() As Person ' Enumerators are positioned before the first element ' until the first MoveNext() call. Dim position As Integer = -1 Public Sub New(ByVal list() As Person) _people = list End Sub Public Function MoveNext() As Boolean Implements IEnumerator.MoveNext position = position + 1 Return (position < _people.Length) End Function Public Sub Reset() Implements IEnumerator.Reset position = -1 End Sub Public ReadOnly Property Current() As Object Implements IEnumerator.Current Get Try Return _people(position) Catch ex As IndexOutOfRangeException Throw New InvalidOperationException() End Try End Get End Property End Class Class App Shared Sub Main() Dim peopleArray() As Person = { _ New Person("John", "Smith"), _ New Person("Jim", "Johnson"), _ New Person("Sue", "Rabon")} Dim peopleList As New People(peopleArray) Dim p As Person For Each p In peopleList Console.WriteLine(p.firstName + " " + p.lastName) Next End Sub End Class ' This code produces output similar to the following: ' ' John Smith ' Jim Johnson ' Sue Rabon
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, 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.



