Rakesh,
Whenever I see someone talk about an issue like this, it screams out why wasn't the code in a class so that it could be reused, and updated by only changing it in one place. The same arguement goes for the one line of code you are trying to put into 300 forms. Shouldn't it be one line of code that you put in a common ancestor class from which all your 300 forms are derived?
>i need to replace several lines of code with a single line of code in about 300 forms and programs, which is the best way to do this?