when you click particular node on treeview, that child only should expand.

Hi, i am having treeview on the screen using asp.net, c#. it works fine. when i click on + symbol , it expand it's child correcly. but , i need that when you click particular node also(which atfer + symbol as text) on treeview, that child only should expand. when you click other treenode, it's child should expand and  before treenode should collapse what we expand early.

pls help me out.
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