Hi ,
When you declare any method in view(S) the life span of that method will be limited to that view..But when you declare the method in component controller ,you can access that method in any controller of your webdynpro component in which it is declared.
But it is not suggested to write application/business logic(S) in your webdynpro component...Better you seperate your application/business logic with presentation logic using assistance class as
Every Web Dynpro application is structured according to the Model View Controller programming model where
1) The model forms the interface to the back end system and thus enables the Web Dynpro application access to data.
2) The view is responsible for the representation of the data in the browser.
3)The controller lies between the view and the model. The controller formats the model data to be displayed in the view, processes the user entries made by the user, and returns them to the model.
Hope this helps you to understand better.Revert back if you need more info..
Thanks
KH