Hakkında herşey C# ReadOnlyCollectionBase Nasıl Kullanılır

Hakkında herşey C# ReadOnlyCollectionBase Nasıl Kullanılır

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With this type from System.Collections.ObjectModel, we provide a collection of elements that cannot be changed. But it may be possible to change some elements themselves.

SingleOrDefault(IEnumerable, TSource) Returns the only element of a sequence, or a specified default value if the sequence is empty; this method throws an exception if there is more than one element in the sequence.

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Bey you suggest, my intention is only to protect the collection from direct modification; the collection members are derece going to be modified (or needed to be modified).

Passing IList/IDictionaries is generally no good because I can't communicate nor enforce the read-only nature of those views (so e.g. IList is actively worse than an array here)

Suppose you need to return a list of all authors from the database birli shown in the code snippet given below.

If your only intent is to get calling code to hamiş make a mistake, and modify the collection when it should only be reading all that is necessary is to return an interface which doesn't support Add, Remove, etc.

Sonuç olarak System.Collections isim alanı altında içinmıza 7 tane non-generic ve 7 adette generic derslik çıkmaktadır. Gerçek önemli olan harbi sınıfı mevsuk yerde kullanmaktır.

Finally, the code example creates an array larger than the collection and uses the CopyTo method to insert the elements of the collection into the middle of the array.

If you do this then there's nothing stopping your callers casting the IEnumerable back to ICollection and then modifying it. ReadOnlyCollection removes this possibility, although it's still possible to access the underlying writable collection via reflection.

However, if you want to access the elements of the IEnumerable collection by index or you want to retrieve the number of elements in the collection, you should use IReadOnlyList bey shown below.

However, a read-only collection doesn't provide Add and Remove methods for changing which items are in the collection, though the items themselves may be C# ReadOnlyCollectionBase Nerelerde Kullanılıyor updateable (it's the responsibility of the items in the collection to protect themselves from changes).

For maximum flexibility, my class doesn't specify the data type of the List in which it keeps its actual veri. Instead, I declare my UnderlyingList variable to use any class that implements the IList interface. I've also made this a generic class: C# ReadOnlyCollectionBase Temel Özellikleri Rather than specify what kind of List I'm working with, I've forced my class to be instantiated with a data type that the code refers to kakım T. Wherever in my code I need to specify my C# ReadOnlyCollectionBase Nedir List's data type, I just use the T reference. Finally, I've chosen to have this class implement the generic version of IEnumerable, which requires two versions of C# ReadOnlyCollectionBase Nerelerde Kullanılıyor the GetEnumerator method -- but the code is identical in C# ReadOnlyCollectionBase Temel Özellikleri both versions of the method. Listing 1. The basics of the PhvReadOnlyList class.

In the class that exposes a read-only property based on PhvReadOnlyList, you still need an ordinary List, with its Add and Remove methods, so that your class dirilik put items in the List both before and after creating a PhvReadOnlyList from it.