ComponentCollection Class

Definition

Namespace:

System.ComponentModel

Assemblies:

netstandard.dll, System.ComponentModel.Primitives.dll

Source:

ComponentCollection.cs

Provides a read-only container for a collection of IComponent objects.

C#

public class ComponentCollection : System.Collections.ReadOnlyCollectionBase

Inheritance

Object

ReadOnlyCollectionBase

ComponentCollection

Examples

The following code example demonstrates how to use a ComponentCollection to enumerate a collection of custom BookComponent objects.

C#

//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 ArgumentException("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 (ArgumentException e)
        {
            Console.WriteLine("Unable to add books: " + 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);
        }
    }
}

Remarks

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 null 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.

Constructors

ComponentCollection(IComponent[])

Initializes a new instance of the ComponentCollection class using the specified array of components.

Properties

Count	Gets the number of elements contained in the ReadOnlyCollectionBase instance. (Inherited from ReadOnlyCollectionBase)
InnerList	Gets the list of elements contained in the ReadOnlyCollectionBase instance. (Inherited from ReadOnlyCollectionBase)
Item[Int32]	Gets the Component in the collection at the specified collection index.
Item[String]	Gets any component in the collection matching the specified name.

Methods

CopyTo(IComponent[], Int32)	Copies the entire collection to an array, starting writing at the specified array index.
Equals(Object)	Determines whether the specified object is equal to the current object. (Inherited from Object)
GetEnumerator()	Returns an enumerator that iterates through the ReadOnlyCollectionBase instance. (Inherited from ReadOnlyCollectionBase)
GetHashCode()	Serves as the default hash function. (Inherited from Object)
GetType()	Gets the Type of the current instance. (Inherited from Object)
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
ToString()	Returns a string that represents the current object. (Inherited from Object)

Explicit Interface Implementations

ICollection.CopyTo(Array, Int32)	Copies the entire ReadOnlyCollectionBase to a compatible one-dimensional Array, starting at the specified index of the target array. (Inherited from ReadOnlyCollectionBase)
ICollection.IsSynchronized	Gets a value indicating whether access to a ReadOnlyCollectionBase object is synchronized (thread safe). (Inherited from ReadOnlyCollectionBase)
ICollection.SyncRoot	Gets an object that can be used to synchronize access to a ReadOnlyCollectionBase object. (Inherited from ReadOnlyCollectionBase)

Extension Methods

Cast<TResult>(IEnumerable)	Casts the elements of an IEnumerable to the specified type.
OfType<TResult>(IEnumerable)	Filters the elements of an IEnumerable based on a specified type.
AsParallel(IEnumerable)	Enables parallelization of a query.
AsQueryable(IEnumerable)	Converts an IEnumerable to an IQueryable.

Applies to

See also

• IComponent