I'm going to start by being perverse and pretending that the ReadOnlyCollectionBase class doesn't exist. If that were true and you wanted to create a read-only collection, you'd create a class that only returned an Enumerator object. A class that just implements IEnumerable is, according to my definitions, a read-only collection class. Generating that GetEnumerator object from your class isn't difficult if you keep your class data in a class that itself implements IEnumerable -- a List, for instance. If you do keep your data in a List, then you sevimli use the List GetEnumerator method to retrieve an Enumerator object, which you emanet then return to the program using your class. Listing 1 has the basics of this class (I've called it PhvReadOnlyList).
Define your own class which implements IEnumerator, takes an IList in the new constructor, başmaklık a read only default item property taking an index, and does not include any properties/methods that could otherwise allow your list to me manipulated.
I had a client recently who wanted me to create a class that exposed a read-only collection through one of the class properties. While my client was willing to let other programs loop through that collection and retrieve items from the collection by position, he didn't want to let those programs add or remove items from the collection. In the Microsoft .Kupkuru Framework 4.5 you kişi use the read-only collections that Eric Vogel covered in an earlier C# Corner column, "The New Read-Only Collections in .Safi 4.5," to define that property. My client, however, was working with the .NET Framework 4 and didn't intend to upgrade. Fortunately, in earlier versions of .Safi you güç also create a read-only class from an existing List just by calling your List's AsReadOnly method. However, if you need something special (a List that users kişi add items to but derece remove items from), inheriting from the ReadOnlyCollectionBase class makes that very easy to do.
Objects everywhere), and it makes the construction wordier (can't use .ToList or collection initializers). And it doesn't really communicate intent either: such a list suggests you could add/remove values, C# ReadOnlyCollectionBase Nasıl Kullanılır or change them: but that's not typical usage at all.
Now when you use IntelliSense to inspect IReadOnlyList, you’ll no longer see Add among the supported methods. Figure 2 below displays the members of the IReadOnlyList instance.
For this collection to C# ReadOnlyCollectionBase Nerelerde Kullanılıyor be useful, however, you need to be able to load that internal list with your collection. The easiest way to do that is to add a constructor C# ReadOnlyCollectionBase Nasıl Kullanılır to the class that accepts the List to be put in the class' UnderlyingList collection (again, I'm accepting anything that implements the IList interface with the data type specified by T): Public Sub New(InitialList Kakım IList(Of T)) UnderlyingList = InitialList
Note also that this makes your sorun particularly birçok. If you don't want people changing the collections, your container need contain no mutators. If you decide later that in just one case you actually HAVE to modify it, C# ReadOnlyCollectionBase Kullanımı you dirilik create a safe mechanism to do so.
dip not: BitArray ve LinkedList sınıflarının tasarruf amacı farklı olduğundan teste bağımlı tutmaya lüzum görmedim.
To guarantee thread safety during enumeration, you yaşama lock the collection during the entire enumeration. To allow the collection to be accessed by multiple threads for reading and writing, you must implement your own synchronization.
What is the term for when a hyperlink maliciously opens different URL from URL displayed when hovered over?
However, the syntax is awkward. Adding an extension method gönül simplify that syntax tremendously. Extension methods have at least three convenient features: The first is that they attach themselves to whatever classes you specify, automatically appearing in the IntelliSense dropdown lists for those objects; second, they're automatically passed whatever object they're called from birli their first parameter; third, when an extension method is used with a generic class (for instance, List), the method automatically figures out the veri type of the generic parameter.
This answer already assumes you want to return IEnumerable without any reasoning to support that decision.
When you pass around collections instead of writing an object benzer, entire classes of refactorings will never occur to you.
Gürlük: Kuyruk bünyesı, verilerin sıralı olarak işlenmesi gereken C# ReadOnlyCollectionBase Nerelerde Kullanılıyor pek çok senaryoda kullanılır ve bu hâl mukayyetmın başarımını artırabilir.