I think our OP is referring back to his other equally vague post about combo boxes and data grid views. In this case he probably wants the combo box choice to be reselected, and the data grid view filter to be restored.
Hopefully, he will come back and clarify what he is asking for. He never went back to his other thread to even tell us whether he is targeting WinForms, WPF, WebForms, or something else.