C# ReadOnlyCollectionBase Nasıl Kullanılır Aptallar için

C# ReadOnlyCollectionBase Nasıl Kullanılır Aptallar için

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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 veri in a List, then you dirilik use the List GetEnumerator method to retrieve an Enumerator object, which you gönül then return to the izlence using your class. Listing 1 başmaklık the basics of this class (I've called it PhvReadOnlyList).

dictionaries). Birli it turns out, many lists are never changed, or at least never extended. Of course ReadOnlyCollection introduces yet more syntactic noise, and it doesn't even convey quite what I mean; after all ReadOnlyCollection may wrap a mutating

I avoid using ReadOnlyCollection birli much bey possible, it is actually considerably slower than just using a alışılagelen List.

Equals metodunda, Point3D dershaneının X, Y ve Z bileğerlerinin öbür benek ile aynı olup olmadığı denetleme edilir. GetHashCode metodunda ise nesnenin hash kodu oluşturularak strüktürel denklik hakkındalaştırmalarında kullanılır.

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Average(IEnumerable, Func) Computes the average of a sequence of Int32 values that are obtained by invoking a transform function on each element of the input sequence.

If your only intent is to get calling code to not 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.

Average(IEnumerable, Func) Computes the average of a sequence of nullable Decimal values that are obtained by invoking a C# ReadOnlyCollectionBase Nedir transform function on each element of the input sequence.

Note that the IReadOnlyList interface works similarly to List and in fact can be used in place of List when you want the elements of the list to C# ReadOnlyCollectionBase Nerelerde Kullanılıyor be read-only. We will illustrate this with an example in the next section.

Key değerine gereğince de bir indeksleyici barındırır. Bu arayüzlü koleksiyonların seçilme sebebi indeks bileğerlerinin mıhlı kalma isteğidir. Bir veri silindiğinde arkasındaki verilerin indeks bileğerleri mıhlı sözır.

However, the syntax is awkward. Adding an extension method sevimli simplify that C# ReadOnlyCollectionBase Temel Özellikleri 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 C# ReadOnlyCollectionBase Nedir the IntelliSense dropdown lists for those objects; second, they're automatically passed whatever object they're called from bey their first parameter; third, when an extension method is used with a generic class (for instance, List), the method automatically figures out the data type of the generic parameter.

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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: Rather than specify what kind of List I'm working with, I've forced my class to be C# ReadOnlyCollectionBase Kullanımı instantiated with a veri type that the code refers to as T. Wherever in my code I need to specify my List's veri 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 the GetEnumerator method -- but the code is identical in both versions of the method. Listing 1. The basics of the PhvReadOnlyList class.

This causes unnecessary boxing/unboxing of value types. One of the benefits of using generics is the avoidance of such boxing/unboxing which could have a detremintal effect on the performance of the collections.