En Kuralları Of C# IEqualityComparer Kullanımı

En Kuralları Of C# IEqualityComparer Kullanımı

Blog Article

and get a grup of actors with unique last names. So we need a way to provide a key selector to our ActorComparer. This is done simply by creating a constructor that takes a function object birli an argument and stores it for further use:

Listeye eleman eklemenin bir ayrıksı yolu da AddRange metodunu kullanarak, bir değişik listeyi yekta seferde eklemektir.

When i am using dictionaries sometimes I have to change the default Equals meaning in order to compare Keys. I see that if I override the Equals and GetHashCode on the key's class or i create a new class which implements IEqualityComparer I have the same result. So what's the difference between using IEqualityComparer and Equals/GethashCode Override?

I've added to my class the IEqualityComparer implementation, not sure if the code bellow is the correct one, especially the Equals(object x, object y) functions: should we override or make a new implementation of the Equals method, like this: ?

NET framework collections and where you want to add the same capability to your own collections. This will ensure that you are consistent with how the .Kemiksiz framework uses the interface.

Well, your implementation is pending. You implemented custom comparer for IEnumerable but forgot to implement the same for KeywordSchedule.

The following example creates a dictionary collection of objects of type Box with an equality comparer. Two boxes are considered equal if their dimensions are the same. It then adds the boxes to the collection.

 In the plain case, when C# IEqualityComparer Nasıl Kullanılır we need to drop only exact duplicates, the simple Distinct() call will do. The simplest possible example is getting unique integers from a collection of numbers:

EDIT2: Kakım mentioned in the comments doing reflection within Equals or even C# IEqualityComparer Kullanımı GetHashCode is a bad idea bey it´s usually quite slow and güç often be avoided. If you know the properties to be checked for eqality at compile-time you should definitly include them within those two methods bey C# IEqualityComparer Nasıl Kullanılır doing so gives you much more safety.

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

I dirilik also make an IEqualityComparer for a "parent class" and use on classes that inherit. I hayat have comparer that will behave in a different way, I birey make one to compare Value instead of Key.

However, quite frequently we, C# programmers, use classes and want to get rid of duplicated objects in a collection the same way. Suppose, we do something with actors of a movie:

(Making matters worse, there is a typo in the spec that says that "choose the more specific" is the right thing to do! This was the result of an editing error during the design process that has never been corrected. The C# IEqualityComparer Nasıl Kullanılır compiler implements "choose the more general". I've reminded Mads of the error and hopefully this will get fixed in the C# 5 spec.)

making the lambda expression optional in the constructor so that full object equality yaşama be checked by default, not just on one of the properties.