Trains Stops and Insert new data using invokeAction!?

Question

Hi! I am using Train element to insert data in some tables. When I open first Train Step I use invokeAction to call CreateInsert operation and could insert new data in table1. Then I go to Train Step 2 and using invokeAction insert data in table2 and so on.
I have two questions:
1. When I go back to previous Train Step using "Back" button then invokeAction again calls CreateInsert operation, but I don't need it. It is possible to call CreateInsert operation using invokeAction ONLY if user goes forward by pressing "Next" button in Train element? If it is possible then What I need to change in my code?
invokeAction source:
<invokeAction Binds="CreateInsert" id="insert_mode"
                  RefreshCondition="${!requestContext.postback and empty bindings.exceptionsList}"
                  Refresh="prepareModel"/>2. It is possible to DISABLE some Train Stopas. For example, I want to disable first Train Stop for user when he go to next steps, so that user can't anymore go back to first Train Stop.
Hope for Your answers, best regards, Debuger!

Answer 1

Hi, Umesh! My use case is following: I am on first Train Stop and enter some data. Then I go to second Stop and enter some data and so on. When I go to first, second etc. Train stops I use invokeAcrion to call CreateInsert. I need to call only this operation when I press next button. When I press Back button I do not need to call Create Insert action. Hope You understand me.
So, as I understand, i need to create method which indicates variable value based which button is pressed. But I don't understand how I can say, variable x=nextbuttonpressed or x=backbuttonpressed based on which button I realy press. And do not understand also how to use this variable in invokeAction Refresh Condition?
Hope You can explain me that with steps to do in my case and can help with code?
Waiting for response, best regards, Debuger.