In my c# application i have this small form which is used to set parameters of application. Once i set the parameters my application runs fine. when i restart the application the values of field in the parametric form are reset.
how can i store and restore the contents of the form between closing and starting of my application
Sounds like you should be storing those configuration values in the App.config file (or one of the other configuration managers .NET provides you).
You can then build your form around serializing and maintaining those values, rather than something custom.
…no need to re-invent the wheel.