Temel İlkeleri C# IStructuralEquatable nerelerde kullanılıyor

If two objects compare as equal, the GetHashCode method for each object must return the same value. However, if two objects do not compare bey equal, the GetHashCode methods for the two object do hamiş have to return different values.

= to provide value equality checks (vs the default reference equality check). The MSDN documentation suggests you only do it for immutable types. There are also issues involving interfaces and operator overloading.

Other types which implement structural equality/comparability include tuples and anonymous types - which both clearly benefit from the ability to perform comparison based on their structure and content. A question you didn't ask is:

Equals and object.ReferenceEquals. Equals is meant to be overridden for whatever sort of comparison makes the most sense for a given type, whereas ReferenceEquals emanet't be overridden and always compares by reference.

Kakım an example, it might make sense for two different instances of an Employee class to be considered equal if they both represent the same entity in your system.

The following example defines a NanComparer class that implements the IStructuralEquatable interface. It compares two Double or two Single values by using the equality operator. It passes values of any other type to the default equality comparer.

After some more testing I found that any two arrays with the same first element have the same hash. I still think this is strange behavior.

Consider that there are only ~4.2 billion different hashcodes. Can you create more than this many different objects of the C# IStructuralEquatable Nasıl kullanılır type on which GetHashCode is called? In this case it is easy to see the answer is "yes". So GetHashCode is a sort of compressing projection onto a smaller set - there are bound to be duplicates.

The first issue we see here is that this struct is mutable in that you birey actually change the data later on via the seki properties. There was no real reason that we introduced this except that we were used to it.

In all my years of development and blogging I never thought I would be writing about how amazing a C# struct is, how awesome IEquatable is, and how C# 7 features make implementing all of it mind blowing.

Ancak, fruits1 ve fruits3 dizileri aynı elemanlara farklı sıralarda ehil başüstüneğundan, CompareTo metodu farklı bir bedel döndürür ve bu dizilerin konstrüktif olarak tay olmadığını belirtir.

Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support.

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. Birli the output from the example shows, the first three method calls return true, whereas the fourth call returns false.

However, this is hamiş so great if you are using the struct in a dictionary kakım my good friend Dustin mentioned to me because a Dictionary will always use the object version of Equals, which falls back to boxing :(