The ICollection Interface: Controlling Access to a Collection in .NET

Drawer Code 128C in .NET The ICollection Interface: Controlling Access to a Collection
The ICollection Interface: Controlling Access to a Collection
Code 128C Generation In .NET Framework
Using Barcode creator for Visual Studio .NET Control to generate, create Code 128C image in VS .NET applications.
You can use the ICollection interface to find out how many items exist within a collection, copy the items from a collection into an array, discover whether the collection provides synchronization for multithreaded scenarios, or access the synchronization object for the collection to implement your own synchronization locking The next collection-oriented interface up the inheritance hierarchy from IEnumerable is the ICollection interface ICollection is derived from IEnumerable, so to implement ICollection, you have to implement IEnumerable as well This interface adds a few members that define some additional attributes about a collection to help control access to the collection items, as described in Table 73 and the following paragraphs
Code 128 Code Set C Recognizer In .NET
Using Barcode recognizer for .NET framework Control to read, scan read, scan image in .NET framework applications.
Table 73 Icollection Interface Members
Bar Code Generation In .NET Framework
Using Barcode generation for .NET framework Control to generate, create bar code image in VS .NET applications.
Member int Count object SyncRoot Description This read-only property returns the number of items in the collection This read-only property returns the object used for performing synchronization locks on the collection This method returns true if the collection is safe for multithreaded access, false otherwise This method lets you copy the items in the collection into an array starting with the item at the specified index
Bar Code Decoder In VS .NET
Using Barcode reader for VS .NET Control to read, scan read, scan image in Visual Studio .NET applications.
bool IsSynchronized
Creating Code 128 Code Set C In C#.NET
Using Barcode creator for VS .NET Control to generate, create Code 128 Code Set B image in .NET applications.
void CopyTo (Array array, int index)
Paint Code-128 In .NET Framework
Using Barcode encoder for ASP.NET Control to generate, create USS Code 128 image in ASP.NET applications.
Probably the most important and frequently used member that is part of the ICollection interface is the Count property If you have a collection that only implements IEnumerable, the only way to figure out how many items are in the collection is to obtain an enumerator for it and iterate through all of the elements, counting how many there are in your own loop That kind of code gets very tedious and is expensive, so collections that implement ICollection let users of the collection obtain the number of items in the collection directly from the Count property, which puts the burden of determining that value on the collection implementerwhere it belongs Usually when you implement ICollection, you will maintain an internal count of the items as they are added and removed, so that the implementation of Count will be fast and easy The CopyTo method lets the consumer of a collection obtain a copy of all the items in the collection in the form of a typed array so that the consumer can operate on those items without worrying about affecting other consumers of the collection CopyTo takes two arguments: a reference to an array and an index that indicates which item in the collection the copying should start with The array that is passed in by the caller has to be of an appropriate type to contain the collection's items and needs to be of sufficient size for all of the items in the collection, starting with the provided index, to be copied into the array Of course, you need to take into account the performance impact of creating a copy of every item in the collection before you use this method If it is acceptable to directly manipulate the items in the collection, don't bother copying them to a separate array first If a collection supports being accessed by multiple threads at a time, it needs to be synchronized This means that it has to implement a locking mechanism to ensure that race conditions cannot arise, such as one thread trying to access an item in the collection that might have been removed by another thread just moments before The details involved in doing this are beyond the scope of this chapter, but there are a number of other books that provide information on that topic (I would suggest Programming NET Components, second edition, by Juval L wy as the definitive source for multithreaded programming and synchronization in NET) The IsSynchronized property indicates whether the collection supports synchronous access from multiple threads If this property returns
Code-128 Printer In VB.NET
Using Barcode printer for .NET framework Control to generate, create Code 128A image in VS .NET applications.
This document was created by an unregistered ChmMagic, please go to http://wwwbisentercom to register it Thanks TRue, then the collection is expected to ensure that it is safe for multiple threads to add, remove, and access items in the collection concurrently If it returns false, then it's up to the user of the collection to ensure that only one thread at a time accesses the collection The latter is the more common case, because adding locking mechanisms to a collection to support concurrent access can have a significant performance penalty for everyone who uses the collection It is usually better to make the few who need concurrent access pay for it in the form of writing more code than to make the many who consume it in a single-threaded way suffer in performance The SyncRoot property provides an object reference that consumers of the collection can use to implement their own locking to support concurrent access The collection is expected to return an object reference that can be used with a Monitor or lock statement, and if the consumer locks on the returned object, then the lock should prevent any other thread from accessing the collection's members while the lock is in place Usually the collection just returns a reference to itself if it is a reference type, and locking on the object itself blocks access to any of the members of the class from another thread until the lock is released However, in certain situations you might use a contained object for locking purposes instead of the collection object itself The bottom line to consumers is that they should be able to take the object reference returned from SyncRoot, lock on it, and know that other threads won't be able to access, add, or delete items in the collection while the lock is in place ICollection<T> is a generic version of the same interface You should also implement this interface if you are creating a strongly typed collection that exposes its count and supports copying and multithreaded access scenarios The factoring of the ICollection<T> and IList<T> interfaces are a little different from their untyped cousins Several of the members of the IList interface are implemented on ICollection<T> in the generic interface inheritance hierarchy, includingAdd, Remove, Contains, Clear, and IsReadOnly (these are discussed in the next section) These all really would make sense to be down at the collection level, since they aren't specific to the ordered, indexed collection notion that IList represents But Microsoft cannot refactor theICollection and IList interfaces at this point, since they have been around since NET 10 and would break immense amounts of legacy code
Barcode Generator In Visual Studio .NET
Using Barcode printer for VS .NET Control to generate, create bar code image in .NET applications.
This document was created by an unregistered ChmMagic, please go to http://wwwbisentercom to register it Thanks
Code 3/9 Creator In Visual Studio .NET
Using Barcode printer for Visual Studio .NET Control to generate, create Code 3/9 image in .NET framework applications.
Make Bar Code In VS .NET
Using Barcode generation for .NET Control to generate, create barcode image in .NET applications.
ISBN - 13 Maker In Visual Studio .NET
Using Barcode creation for Visual Studio .NET Control to generate, create International Standard Book Number image in .NET applications.
Making UCC-128 In Visual Studio .NET
Using Barcode maker for ASP.NET Control to generate, create USS-128 image in ASP.NET applications.
USS Code 39 Creation In Visual Studio .NET
Using Barcode encoder for ASP.NET Control to generate, create ANSI/AIM Code 39 image in ASP.NET applications.
EAN13 Decoder In .NET Framework
Using Barcode recognizer for VS .NET Control to read, scan read, scan image in VS .NET applications.
Decoding Code 39 In .NET Framework
Using Barcode decoder for .NET framework Control to read, scan read, scan image in VS .NET applications.