IN Datagridview when first column combobox value changes then second column combobox selected values should clear

IN Datagridview when first column combobox value changes then second
column combobox selected values should clear

In datagridview i have two combobox columns and combobox2 get items based
on combobox1 selection.
It works good for the first row but when coming to the second row it works
fine same but first row combobox2 items changes to the combobox2 items in
second row.and when i want to change the combobox1 value combobox2 items
must clear first values and fill with latest values Please tell me what is
the solution for this