any one can reply me
You can’t expect to learn object-oriented programming just by asking such questions in forums. Internet is full of articles, tutorials, videos, training courses (such as Microsoft Virtual Academy) that will help you with that, without having to pay anything.
this is a reference to the object in which you’re running your code.
parmArgs() is a method of the object references by the variable (this, in this case).
Most likely parmArgs() returns a value - a reference to an instance (= object) of Args class, which holds certain parameters. What value you can find there depends on the context.
Also, please make sure you ask in the right forum (this belongs to the developer forum, therefore I’m going to move it there).