Check uniqueness in rows of treeview

[Kamalpreet Grewal <grewalkamal005 gmail com>]

Is there any way to make sure that rows with same data are not added
to treeview? I want a treeview in which each row of the treeview has
unique row content.

Say a row with content 'hello' exists, the next time I attempt to add
a row with same content, the duplicate row isn't appended to the
treeview. I have explored various examples to achieve this, but no
luck so far. How can this be achieved?

-- 
Kamalpreet Kaur Grewal
Blog: http://kamalpreetgrewal.com/