Is it possible define an extension operator method?

Question

is it possible to define an extension method that at the same time is an operator? I want for a fixed class add the possibility to use a known operator that actually can\'t

Answer 1

No, you can't have an extension method which is also an operator. Extension methods can only be declared in static classes, which can't have instances and according to the C# spec,

User-defined operator declarations always require at least one of the parameters to be of the class or struct type that contains the operator declaration. [7.3.2]

Therefore, it is impossible for an extension method to also be an overloaded operator.

Additionally, you can't override System.String since it is a sealed class.