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Why can't the keyword this be used in a static method? I am wondering why C# defines this constraint. What benefits can be gained by this constraint?
[Update]: Actually, this is a question I got in an interview. I do know the usage of 'static' and 'this', based on all your response, I guess I know a little of why the two can not be used together. That is, for static method is used to changed state or do something in a type level, but when you need to use 'this' means you want to change the state or do something in a instance level. In order to differentiate the state change of a type and the state change of an instance, then c# donot allow use 'this' in a static method. Am I right?
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In order to call a static method or property within another static method of the same class, you can use the this keyword.
But static contexts(methods and blocks) doesn't have any instance they belong to the class. In a simple sense, to use “this” the method should be invoked by an object, which is not always necessary with static methods. Therefore, you cannot use this keyword from a static method.
Namely, static methods can only use static variables and call static methods—they cannot access instance variables or methods directly, without an object reference. This is because instance variables and methods are always tied to a specific instance, i.e., object of their class.
Where the "super" keyword in Java is used as a reference to the object of the superclass. This implies that to use "super" the method should be invoked by an object, which static methods are not. Therefore, you cannot use the "super" keyword from a static method.
Because this points to an instance of the class, in the static method you don't have an instance.
The this keyword refers to the current instance of the class. Static member functions do not have a this pointer
You'll notice the definition of a static member is
Use the static modifier to declare a static member, which belongs to the type itself rather than to a specific object
Which is why this has nothing to point to.
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