How to get Controls in infopath forms programming

I have do some customizations in the infopath forms , so i have choose edit form the code option when a button clicked...I would like to know how can we开发者_如何学Python get the control ids in the code.please let me know how to start with the programing in infopath.

Eg: string fieldValue = MainDataSource.CreateNavigator().SelectSingleNode( "/my:myFields/my:field1", NamespaceManager).Value;