Get a control from tab1 from tab 2 of a tabcontrol

Question

i have a form with a tab control it has 2 tabs one has a user datagrid control
the other has a user control this control can be one of many(it is a detail control specific to the type of entity selected (user, company, department)

in the datagrid control when a user wants to edit details, the user double clicks a row and i want to pass the data row from the grid on tab 2 to the user control on tab 1.

i did the code to get the datarow, but dont know how to pass it to the tab1 user control, how can i do that ?