Pass Variable From Controller to DataProvider

Goodmorning

Some report (in this specific case the SalesPackingSlip) does not have a request page to set parameters.
The user can only choose between two different menu items (Copy/Original Preview).
It may be possible to apply this logic also to a customization?

for example, I would like to:

- create a new menu’ item
- check the caller menu into the SalesPackingSlipController(main) and use it to pass a new variable to the SalesPackingSlipDP:

          if(_args.menuItemName()         ==  "xxxx")

        {

            SalesPackingSlipDP.M_paramDelDate("HideDate");

        }

 - Use my new variable when the data provider fills the PurchPackingSlipHeaderTmp.

Right now I get the error that SalesPackingSlipDP is not initialized, and I cannot figure out how to solve it.
Do you have any suggestion in how to mange that?
Since I’ve just start working on AX, I may be completely out of track here, so let me know if there is a correct way to manage that customization.

Thanks