Tags and Treeview nodes

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C#

Can someone explain to me the proper use of tags. I was thinking it was just that a reference to the node. so you can look them up or whatever. Am I missing something here?

<pre>
string[] AuthorNames = new string[bookdbDataSet.Tables[0].Rows.Count];
int row=0;
foreach (DataRow Row in bookdbDataSet.Tables[0].Rows)
{
AuthorNames[row] = Row["AuthorFirst"].ToString() + " " + Row["AuthorLast"].ToString();
TreeNode tn = new TreeNode(Row["AuthorLast"].ToString() + ',' + Row["AuthorFirst"].ToString());
tn.Tag ="2"
rootNode.Nodes.Add(tn);

row++;
}
</pre>


whenever I take and do a selectnode from the treeview for some reason the tag is always null even though I thought I was setting it to the value of 2... I that not what the tag is for ? If it is could you please explain to me what i might be doing wrong. thank you so much for all the help this board has given me.