Tree view control

Question

Hi,
i am having one problem.i have used a tree view control in master page  whice have been populated dynamically from the database(Ms sql).When i click on a child node a page should open in a content page only.but in my case when a user clicks on a child node whole page gets refreshed. Another problem is when a user clicks on a child node , all the child nodes also gets collapse.what should i do to retain childnodes expanded .i have tried treenode.expandall(); properties but it expand tree node on pageload . i dont want it.what i need to do is , a tree view collapsed on pageload and when a user clicks on a parent node then only child node should expand and it should remain expanded until a user wants it to collapse .plz help me as soon as possible.
thanks in advance