ICollection.cs source code in C# .NET

                        
Code:
                         / 4.0 / 4.0 / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / clr / src / BCL / System / Collections / ICollection.cs / 1305376 / ICollection.cs
                        

                        
                            // ==++== 
//
//   Copyright (c) Microsoft Corporation.  All rights reserved.
//
// ==--== 
/*============================================================
** 
** Interface:  ICollection 
**
** [....] 
**
**
** Purpose: Base interface for all collections.
** 
**
===========================================================*/ 
namespace System.Collections { 
    using System;
    using System.Diagnostics.Contracts; 

    // Base interface for all collections, defining enumerators, size, and
    // synchronization methods.
    [ContractClass(typeof(ICollectionContract))] 
    [System.Runtime.InteropServices.ComVisible(true)]
    public interface ICollection : IEnumerable 
    { 
        // Interfaces are not serialable
        // CopyTo copies a collection into an Array, starting at a particular 
        // index into the array.
        //
        void CopyTo(Array array, int index);
 
        // Number of items in the collections.
        int Count 
        { get; } 

 
        // SyncRoot will return an Object to use for synchronization
        // (thread safety).  You can use this object in your code to take a
        // lock on the collection, even if this collection is a wrapper around
        // another collection.  The intent is to tunnel through to a real 
        // implementation of a collection, and use one of the internal objects
        // found in that code. 
        // 
        // In the absense of a static Synchronized method on a collection,
        // the expected usage for SyncRoot would look like this: 
        //
        // ICollection col = ...
        // lock (col.SyncRoot) {
        //     // Some operation on the collection, which is now thread safe. 
        //     // This may include multiple operations.
        // } 
        // 
        //
        // The system-provided collections have a static method called 
        // Synchronized which will create a thread-safe wrapper around the
        // collection.  All access to the collection that you want to be
        // thread-safe should go through that wrapper collection.  However, if
        // you need to do multiple calls on that collection (such as retrieving 
        // two items, or checking the count then doing something), you should
        // NOT use our thread-safe wrapper since it only takes a lock for the 
        // duration of a single method call.  Instead, use Monitor.Enter/Exit 
        // or your language's equivalent to the C# lock keyword as mentioned
        // above. 
        //
        // For collections with no publically available underlying store, the
        // expected implementation is to simply return the this pointer.  Note
        // that the this pointer may not be sufficient for collections that 
        // wrap other collections;  those should return the underlying
        // collection's SyncRoot property. 
        Object SyncRoot 
        { get; }
 
        // Is this collection synchronized (i.e., thread-safe)?  If you want a
        // thread-safe collection, you can use SyncRoot as an object to
        // synchronize your collection with.  If you're using one of the
        // collections in System.Collections, you could call the static 
        // Synchronized method to get a thread-safe wrapper around the
        // underlying collection. 
        bool IsSynchronized 
        { get; }
    } 

    [ContractClassFor(typeof(ICollection))]
    internal class ICollectionContract : ICollection
    { 
        void ICollection.CopyTo(Array array, int index)
        { 
        } 

        int ICollection.Count { 
            get {
                Contract.Ensures(Contract.Result() >= 0);
                return default(int);
            } 
        }
 
        Object ICollection.SyncRoot { 
            get {
                Contract.Ensures(Contract.Result