C# IEqualityComparer Temel Özellikleri ve Kullanımı Günlükler

C# IEqualityComparer Temel Özellikleri ve Kullanımı Günlükler

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The last statement basically means that in case we rely on Equals(..) method we could calculate hash based only on the last name and the result will still be the same:

Note that IEqualityComparer may (and should) be used to perform more complex comparisons, however its implementation won't get much more complex in most cases.

Besides, it allows to use more than one property bey a key, so the next call is absolutely valid and will preserve all actors with the same last name as long birli their first names differ:

What's the necessary and sufficient condition for a real sequence to be written birli the self-convolution of another real sequence?

This was a point of some debate and there are arguments on three sides: choose the more specific of the types, choose the more general of the types, or have type inference işleyen. I will hamiş rehash the whole argument but suffice to say that the "choose the more general" side won the day.

Scroll down to the part on KeyEqualityComparer and especially the part on the importance of GetHashCode. There is a whole discussion on why obj.GetHashCode(); (birli suggested by DMenT's post) is wrong and should just return 0 instead.

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.

While MSDN is a valuable resource, don't take everything MSDN says as gospel. MSDN contains plenty of bad advice, outdated, badly written or plain wrong content.

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

What would C# IEqualityComparer Nasıl Kullanılır you expect the type of positions to be? Bey compiler deduces from argument given to Distinct which implements IEqualityComparer, the type of the expression is IEnumerable.

We will make the previous example, but we’ll C# IEqualityComparer Kullanımı use GenericEqualityComparer class. Remember this class isn’t only suitable for any customer field or any customer field’s C# IEqualityComparer Nasıl Kullanılır combination, but also for any field class or any field’s combination of any class.

Isn't it problematic to look at the data to decide to use a parametric vs. non-parametric sınav? more hot questions

What Distinct() actually does here is comparing object references. So our second George Clooney is in fact an independent object (since it was created independently) and its reference differs from the reference of the first one - therefore it appears in the output twice:

Equals/GetHashCode not only internalizes comparison logic, but also globalize them. There might be cases where I C# IEqualityComparer Nasıl Kullanılır would like internal comparison (derece using collection) for just one time.