Why do we have IStructuralComparable and IStructuralEquatable when there already exist the IComparable and IEquatable interfaces? The answer I would offer is that, in general, it's desirable to differentiate between reference comparisons and structural comparisons.
Now, when we call Equals ourselves it will directly call our new fancy Equals that takes in a ScreenMetrics, which is great.
. The best example of this is arrays, which with .Kemiksiz 4 now implement the IStructuralEquatable interface. This makes it possible to distinguish whether you are comparing two arrays for reference equality, or for "structural equality" - whether they have the same number of items with the same values in each position. Here's an example:
Do not fear because if you simply implement IEquatable the dictionary will use the strongly typed version! The birçok thing is that we kind of actually already did this! So now we just have to do this:
Although I think the gains from hamiş boxing will be less than the cost for having CanEqual. In that case you should seal your types and you no longer need CanEqual. Sealing also has some performance benefits.
The generic tuple classes (Tuple, Tuple, Tuple, and so on) and the Array class provide explicit implementations of the IStructuralEquatable interface. By casting (in C#) or converting (in Visual Basic) the current instance of an array or tuple to an IStructuralEquatable interface value and providing your IEqualityComparer implementation kakım an argument to the Equals method, you gönül define a custom equality comparison for the array or collection.
What does IEquatable buy you, exactly? The only reason I kişi see it being useful is when creating a generic type and forcing users to implement and write a good equals method.
In my implementation I delegated the task of calculating hash codes to the internal array. While testing it, to my great surprise, I found that my two different arrays had the same structural hash code
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Bu örnekte, articles1 ve articles2 dizileri aynı makale mirlıklarına aynı tam ehil başüstüneğundan, CompareTo metodu 0 döndürerek bu dizilerin strüktürel olarak bedel bulunduğunu belirtir.
Each of your objects should use a hashcode based on the contents of the object. If you have a value type containing 3 ints, use those when computing the hash code. Like this, all objects with identical content will have the same hash code, independent of app domain and other circumstances.
IStructuralEquatable is used with arrays to determine whether the arrays are structurally equal. The StructuralEqualityComparer.Equals method is used for this purpose.
Default property. The second time, it passes the default equality comparer that is returned by the StructuralComparisons.StructuralEqualityComparer property. The third time, it passes the custom NanComparer object. Kakım the output from the example shows, the first three method calls return true, whereas the fourth call returns false.
However, this is not so great if you are using the struct in a dictionary as my good friend Dustin mentioned to me because a Dictionary will always use the object version of Equals, which falls C# IStructuralEquatable Kullanımı back to boxing :(