ComponentCollection Class
Assembly: System (in system.dll)
'Declaration <ComVisibleAttribute(True)> _ Public Class ComponentCollection Inherits ReadOnlyCollectionBase 'Usage Dim instance As ComponentCollection
/** @attribute ComVisibleAttribute(true) */ public class ComponentCollection extends ReadOnlyCollectionBase
ComVisibleAttribute(true) public class ComponentCollection extends ReadOnlyCollectionBase
Not applicable.
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 a null reference (Nothing in Visual Basic) 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
// 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 ArrayList mBookList;
public LibraryContainer()
{
mBookList = new ArrayList();
} //LibraryContainer
public void Add(IComponent book)
{
// The book will be added without creation of the ISite object.
mBookList.Add(book);
} //Add
public void Add(IComponent book, String isndNNum) throws SystemException
{
for (int i = 0; i < mBookList.get_Count(); ++i) {
IComponent curObj = (IComponent)mBookList.get_Item(i);
if (curObj.get_Site() != null) {
if (curObj.get_Site().get_Name().Equals(isndNNum)) {
throw new SystemException(
"The ISBN number already exists in the container");
}
}
}
ISBNSite data = new ISBNSite(this, book);
data.set_Name(isndNNum);
book.set_Site(data);
mBookList.Add(book);
} //Add
public void Remove(IComponent book)
{
for (int i = 0; i < mBookList.get_Count(); ++i) {
if (book.Equals(mBookList.get_Item(i))) {
mBookList.RemoveAt(i);
break;
}
}
} //Remove
/** @property
*/
public ComponentCollection get_Components()
{
IComponent dataList[] = new BookComponent[mBookList.get_Count()];
mBookList.CopyTo(dataList);
return new ComponentCollection(dataList);
} //get_Components
public void Dispose()
{
for (int i = 0; i < mBookList.get_Count(); ++i) {
IComponent curObj = (IComponent)mBookList.get_Item(i);
curObj.Dispose();
}
mBookList.Clear();
} //Dispose
public static void main(String[] args)
{
LibraryContainer cntrExmpl = new LibraryContainer();
try {
BookComponent book1 = new BookComponent("Wizard's First Rule",
"Terry Gooodkind");
cntrExmpl.Add(book1, "0812548051");
BookComponent book2 = new BookComponent("Stone of Tears",
"Terry Gooodkind");
cntrExmpl.Add(book2, "0812548094");
BookComponent book3 = new BookComponent("Blood of the Fold",
"Terry Gooodkind");
cntrExmpl.Add(book3, "0812551478");
BookComponent book4 = new BookComponent("The Soul of the Fire",
"Terry Gooodkind");
// This will generate exception because the ISBN already exists in
// the container.
cntrExmpl.Add(book4, "0812551478");
}
catch (SystemException e) {
Console.WriteLine("Error description: " + e.get_Message());
}
ComponentCollection dataList = cntrExmpl.get_Components();
IEnumerator denum = dataList.GetEnumerator();
while (denum.MoveNext()) {
BookComponent cmp = (BookComponent)denum.get_Current();
Console.WriteLine("Book Title: " + cmp.get_Title());
Console.WriteLine("Book Author: " + cmp.get_Author());
Console.WriteLine("Book ISBN: " + cmp.get_Site().get_Name());
}
} //main
} //LibraryContainer
Windows 98, Windows Server 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.