En C# IEqualityComparer nerelerde kullanılıyor Sırları

En C# IEqualityComparer nerelerde kullanılıyor Sırları

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Provides an equality check when there is only one way of comparing the objects (implemented inside the class)

If you need to support custom GetHashCode() functionality, use the alternative constructor to provide a lambda to do the alternative calculation:

Kişi a unique position be deduced if pieces are replaced by checkers (kişi see piece color but not type)

Because you need an instance and derece just a method call you dirilik't let the generic type be inferred by the compiler (see this discussion) but have to do so when creating the instance:

Notice that I didn't have to override Equals, GetHashCode in neither of the classes. I birey use this comparer in any object that implements ICustom without having to rewrite the comparison logic.

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I now need to do distinct on a collections of some of these objects. I have the following code over and over for each of the child classes:

After inspecting multiple SO questions and answers related to the topic birli well as some C# IEqualityComparer Kullanımı other articles I have both found the solution that fitted my needs for the moment and got some understanding of the way IEqualityComparer is actually used by LINQ operators. Here I will try to explain what I got from there.

This interface allows the implementation of customized equality comparison C# IEqualityComparer nerelerde kullanılıyor for collections. That is, you yaşama create your own definition of equality, and specify that this definition be used with a collection type that accepts the IEqualityComparer interface.

Eric's answer explains the root cause of C# IEqualityComparer Nasıl Kullanılır the whole issue (in terms of covariance and contravariance).

When we make the inference from allPositions to IEnumerable we say "IEnumerable is covariant C# IEqualityComparer Nasıl Kullanılır in T, so we birey accept Position or any larger type

Yeni bir referans tipi değsorunkeni oluşturulduğunda, yalnızca bir referans oluşturulur ve bellekteki veri bu referansın gösterdiği yerde C# IEqualityComparer Nasıl Kullanılır saklanır.

For example if you class implements IEntity which has an Id property, you could then use a comparison class for all equality checks that implements IEqualityComparer.

If there are multiple ways instances of a class could be considered equal. The best example of this is a string, for which the framework provides six different comparers in StringComparer.