How have you built your dialog? From code? Maybe using a UI builder class? Or is it a modeled form?
With which part of your requirement do you need a help? Maybe you don’t know what you can use enabled() method enable and disable controls. Or maybe you don’t know how to get a reference to your new button. Or something else?
Actually i am calling this dialog form through my customized class
there are so many class which is called this dialog form so i just want to show only one extra button only for
particular class and remain same as it is for all other class
Is your class extending any other class? Then code might be in the dialog method of that class. Some code should be there in the system which is generating this dialog that you see.
Dialog method in smmUpdateFinancial class has the code from which dialog is generated.
If multiple classes are calling this class, then you can setup a parameter method in this class to know from where it is called or simply use the caller function if you can.
Refer the following link, which describes how you can enable/disable a button on custom dialogs: