ComponentCollection Class
Provides a read-only container for a collection of IComponent objects.
Assembly: System (in System.dll)
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The HostProtectionAttribute attribute applied to this type or member has the following Resources property value: Synchronization. The HostProtectionAttribute does not affect desktop applications (which are typically started by double-clicking an icon, typing a command, or entering a URL in a browser). For more information, see the HostProtectionAttribute class or SQL Server Programming and Host Protection Attributes. |
This collection inherits from ReadOnlyCollectionBase. The only way to add IComponent objects to this collection is to use the class constructor.
This collection provides two indexer properties, a string indexer and an integer indexer. The string indexer property returns a component in the collection by name if the Site property of a component in the collection is not Nothing and the Name property of the Site property of the component matches the specified string. The integer indexer property returns the IComponent at the specified collection index. The CopyTo method copies the contents of the collection to a specified array, beginning writing to the array at the specified index.
The following code example demonstrates how to use a ComponentCollection to enumerate a collection of custom BookComponent objects.
'This code segment implements the IContainer interface. The code segment 'containing the implementation of ISite and IComponent can be found in the documentation 'for those interfaces. 'Implement the LibraryContainer using the IContainer interface. Class LibraryContainer Implements IContainer Private m_bookList As ArrayList Public Sub New() m_bookList = New ArrayList() End Sub Public Sub Add(ByVal book As IComponent) Implements IContainer.Add 'The book will be added without creation of the ISite object. m_bookList.Add(book) End Sub Public Sub Add(ByVal book As IComponent, ByVal ISNDNNum As String) Implements IContainer.Add Dim i As Integer Dim curObj As IComponent For i = 0 To m_bookList.Count - 1 curObj = CType(m_bookList(i), IComponent) If curObj.Site IsNot Nothing Then If (curObj.Site.Name.Equals(ISNDNNum)) Then Throw New SystemException("The ISBN number already exists in the container") End If End If Next i Dim data As ISBNSite = New ISBNSite(Me, book) data.Name = ISNDNNum book.Site = data m_bookList.Add(book) End Sub Public Sub Remove(ByVal book As IComponent) Implements IContainer.Remove Dim i As Integer Dim curComp As BookComponent = CType(book, BookComponent) For i = 0 To m_bookList.Count - 1 If (curComp.Equals(m_bookList(i)) = True) Then m_bookList.RemoveAt(i) Exit For End If Next i End Sub Public ReadOnly Property Components() As ComponentCollection Implements IContainer.Components Get Dim datalist(m_bookList.Count - 1) As IComponent m_bookList.CopyTo(datalist) Return New ComponentCollection(datalist) End Get End Property Public Overridable Sub Dispose() Implements IDisposable.Dispose Dim i As Integer For i = 0 To m_bookList.Count - 1 Dim curObj As IComponent = CType(m_bookList(i), IComponent) curObj.Dispose() Next i m_bookList.Clear() End Sub Public Shared Sub Main() Dim cntrExmpl As LibraryContainer = New LibraryContainer() Try Dim book1 As BookComponent = New BookComponent("Wizard's First Rule", "Terry Gooodkind") cntrExmpl.Add(book1, "0812548051") Dim book2 As BookComponent = New BookComponent("Stone of Tears", "Terry Gooodkind") cntrExmpl.Add(book2, "0812548094") Dim book3 As BookComponent = New BookComponent("Blood of the Fold", "Terry Gooodkind") cntrExmpl.Add(book3, "0812551478") Dim book4 As BookComponent = New BookComponent("The Soul of the Fire", "Terry Gooodkind") 'This will generate an exception, because the ISBN already exists in the container. cntrExmpl.Add(book4, "0812551478") Catch e As SystemException Console.WriteLine("Error description: " + e.Message) End Try Dim datalist As ComponentCollection = cntrExmpl.Components Dim denum As IEnumerator = datalist.GetEnumerator() While (denum.MoveNext()) Dim cmp As BookComponent = CType(denum.Current, BookComponent) Console.WriteLine("Book Title: " + cmp.Title) Console.WriteLine("Book Author: " + cmp.Author) Console.WriteLine("Book ISBN: " + cmp.Site.Name) End While End Sub End Class
Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98
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.
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