. NET

Method	Category	Class default behavior	NativeClassType	EndStructure	DifferentType SimilarityAnd so on	LineIs it possible to overrideWrite	Application fieldJing
Object. Equals	Static Method	Call the Equals instance method	Equal Value	Field Values are equal	Yes	Yes	The parameter may be Null.
Object. ReferenceEquals	Static Method	References are equal	Returns False.	Returns False.	Not Allowed	Not Allowed	Test
=	Operator	References are equal	Equal Value	Must be defined before use	Not Allowed	Yes	Native type, simple business logic
Equals	Instance method	References are equal	The value and type are equal.	Field Values are equal	Yes	Yes	General Processing

For the value type, the implementation = operation is like an embellishment. If you want to implement equal comparison operations, you should first override the Equals method (similarly, If You Want To implement size comparison, you should first implement
IComparable interface instead of comparison operator). When the Equals method inherited from the Object is used for value type, all fields of the two objects are compared.
True. It is said that reflection is used, and the efficiency is very low. However, if it is low, why must it be overwritten first?

Because all. Net
The Framework Key-value set is compared using the Equals instance method, so it is actually a legal balance in. Net, whether it is a native type, structure or class instance, it should be
The Equals method serves as its standard equal comparison method, including the types we implement ourselves. The benefits of using the instance method can also be understood, more flexible, we can add some overloaded Equals method
Different prerequisites for comparison. Works with the default rewritten Equals method to form a complete set of comparison rules to meet the complex and variable standards in reality.

When rewriting the Equals method, the official recommendation is to rewrite the GetHashCode method. If you don't use this type as the key-value set key, it doesn't matter.

In some cases, when the complexity is to overload the Equals method, we need to define a function class dedicated to comparing equal .. Net
The Framework already provides an interface System. Collections. IEqualityComparer and has several built-in implementations, such
For StringComparer and EqualityComparer, the comparison class we write may also implement this interface. Of course, as long as it can be used, you don't have to worry about that much. View. Net
Framework source code, you can find that many messy classes are used to compare equal, probably internal privileges.

Part of the full text of the link: http://www.cnblogs.com/XmNotes/archive/2011/06/23/2088341.html