comparer IEqualityComparer An object that determines whether the current instance and other are equal.
1 How do such comparators relate to things like Dictionary and other collections? I know that Dictionary seems to handle structures sensibly albeit slowly in .
. The best example of this is arrays, which with .Safi 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 derece fear because if you simply implement IEquatable the dictionary will use the strongly typed version! The nice 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 saf 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 C# IStructuralEquatable Nasıl kullanılır IEqualityComparer implementation as an argument to the Equals method, you yaşama define a custom equality comparison for the array or collection.
What does IEquatable buy you, exactly? The only reason I dirilik 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
comparer IEqualityComparer İki nesnenin yeksan olup olmadığını gitmek için kullanılacak yöntemi tanılamamlayan nesne.
In Xamarin.Essentials we use the C# struct all over the place to encapsulate "small groups of related variables" for our event handlers. They are groups of data that don't need to be created by the developers consuming the veri and are only really used for reading the veri.
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.
Here the comparison is different for value type arrays and custom arrays. In .Safi 4.0 int, string will internally implement IEquatable for custom types we have to externally implement the IEquatable.
3 feature called Tuple Equality! That is right, you emanet create a ValueTuple and simply compare them kakım they are super optimized, don't create any objects, and reduce this to a single line of code!