ComponentCollection 类

项目
08/17/2007

为 IComponent 对象的集合提供只读容器。

**命名空间:**System.ComponentModel
**程序集:**System（在 system.dll 中）

语法

声明
<ComVisibleAttribute(True)> _
Public Class ComponentCollection
    Inherits ReadOnlyCollectionBase
用法
Dim instance As ComponentCollection

[ComVisibleAttribute(true)] 
public class ComponentCollection : ReadOnlyCollectionBase

[ComVisibleAttribute(true)] 
public ref class ComponentCollection : public ReadOnlyCollectionBase

/** @attribute ComVisibleAttribute(true) */ 
public class ComponentCollection extends ReadOnlyCollectionBase

ComVisibleAttribute(true) 
public class ComponentCollection extends ReadOnlyCollectionBase

备注

此集合从 ReadOnlyCollectionBase 继承。将 IComponent 对象添加到此集合的唯一方式就是使用类构造函数。

此集合提供两个索引器属性、一个字符串索引器和一个整数索引器。如果集合中某个组件的 Site 属性不为空引用（在 Visual Basic 中为 Nothing），且该组件的 Site 属性的 Name 属性与指定的字符串匹配，则字符串索引器属性返回集合中该组件的名称。整数索引器属性返回指定集合索引处的 IComponent。CopyTo 方法将集合的内容复制到指定的数组，在指定的索引处开始对数组进行写入。

提示

应用于此类的 HostProtectionAttribute 属性 (Attribute) 具有以下 Resources 属性 (Property) 值：Synchronization。HostProtectionAttribute 不影响桌面应用程序（这些应用程序通常通过双击图标、键入命令或在浏览器中输入 URL 来启动）。有关更多信息，请参见 HostProtectionAttribute 类或 SQL Server 编程和宿主保护属性。

示例

下面的代码示例演示如何使用 ComponentCollection 来枚举自定义 BookComponent 对象的集合。

   '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 Not curObj.Site Is 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 : IContainer
{
    private ArrayList m_bookList;

    public LibraryContainer()
    {
        m_bookList = new ArrayList();
    }

    public virtual void Add(IComponent book)
    {
        //The book will be added without creation of the ISite object.
        m_bookList.Add(book);
    }

    public virtual void Add(IComponent book, string ISNDNNum)
    {
        for(int i =0; i < m_bookList.Count; ++i)
        {
            IComponent curObj = (IComponent)m_bookList[i];
            if(curObj.Site != null)
            {
                if(curObj.Site.Name.Equals(ISNDNNum))
                    throw new SystemException("The ISBN number already exists in the container"); 
            }
        }

        ISBNSite data = new ISBNSite(this, book);
        data.Name = ISNDNNum;
        book.Site = data;
        m_bookList.Add(book);
    }

    public virtual void Remove(IComponent book)
    {
        for(int i =0; i < m_bookList.Count; ++i)
        {                
            if(book.Equals(m_bookList[i]))
            {
                m_bookList.RemoveAt(i);
                    break;
            }
        }
    }

    public ComponentCollection Components
    {
        get
        {
            IComponent[] datalist = new BookComponent[m_bookList.Count];
            m_bookList.CopyTo(datalist);
            return new ComponentCollection(datalist);
        }
    }

    public virtual void Dispose()
    {    
        for(int i =0; i < m_bookList.Count; ++i)
        {
            IComponent curObj = (IComponent)m_bookList[i];
            curObj.Dispose();
        }
        
        m_bookList.Clear();
    }

    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.Message);
        }

        ComponentCollection datalist =cntrExmpl.Components;
        IEnumerator denum = datalist.GetEnumerator();

        while(denum.MoveNext())
        {
            BookComponent cmp = (BookComponent)denum.Current;
            Console.WriteLine("Book Title: " + cmp.Title);
            Console.WriteLine("Book Author: " + cmp.Author);
            Console.WriteLine("Book ISBN: " + cmp.Site.Name);
        }
    }
}

// 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

继承层次结构

System.Object
System.Collections.ReadOnlyCollectionBase
System.ComponentModel.ComponentCollection

线程安全

此类型的任何公共静态（Visual Basic 中的 Shared）成员都是线程安全的，但不保证所有实例成员都是线程安全的。

平台

Windows 98、Windows 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

.NET Framework 并不是对每个平台的所有版本都提供支持。有关受支持版本的列表，请参见系统要求。

通过

ComponentCollection 类

语法

备注

示例

继承层次结构

线程安全

平台

版本信息

.NET Framework

请参见

参考

其他资源