Drag and drop problem

hi,

In my project in a treeview i am doing drag and drop function and
after that modifying some values in a treeview ascending order of
nodes, some times the treeview may contain 255 nodes each child node
with morethan 50 childnodes,

i am using for loop for rearranging the nodes inside it i am modifying
values , it is too taking too much time for 100 and more nodes
morethan 5 minutes

can anybody help me in this regards?