parent and child data both are from different table but in application i want to show all parent and child data into one column every parent and child come to new column every time which control i use

Parent is Categorory
child is Subcategory and both are from different table having primary and foriegn key relation both are varchar datatype
i want to display in parent and child like

parent(A) parent(B) parent(c)
child1 (A) child (B) child(c)
child2 (A) child (B) child(c)
like that manner