populate tree view

Question

how to populate tree view from single table with parent child relation

This is my table

GrpId       GrpName        PId
*********************
1             Department       0
2             Grp1                 1                
3             Admin               2
4             Sales                2
5             Purchase           3
6             Grp2                 1
7             Finance             6
8             Production         6

I want the result as like this

Department
----Grp1
-------Admin
-------Sales
-------Purchase
----Grp2
-------Finance
-------Production