Get the Selected Item Text from the treeview control

I populate the data to a treeview where i need to get the selected text. How to do it..
Below is the code in page_load event.

private void Page_Load(object sender, System.EventArgs e)
{
if(!IsPostBack)
{
strSql="Select contentid,headline,menucaption,menulevel,parentmenuorder,";
strSql+="release,contentno from tblcontent";
// Establish Connection
SetConnection();
objContentDa = new OdbcDataAdapter(strSql,ObjCon);
objDs = new DataSet();
objContentDa.Fill(objDs,"Content");
//Clean up.
objDs.Dispose();
objContentDa.Dispose();
ObjCon.Close();
//Populate the TreeView from the DataSet.
foreach (DataRow rowContent in objDs.Tables["Content"].Rows)
{
nodeContent = new TreeNode();
nodeContent.Text = rowContent["menucaption"].ToString();
TreeView1.Nodes.Add(nodeContent);
}
}
When I press a button (server control) i need to get the text on which the user selected the node.

Thanks in advance