display contents on a textbox on clicking tree node value

Question

Hi all,
 
I have a tree view with parent and child nodes. If i click on a nodes, I want the description about that node in a textbox. this should happen for all the nodes. how should I do this.
 
My code behind I have tried is:

private void fetchtreeview()
{
TVContent.Nodes.Clear(); 
DataTable topics = dsSOW.Tables["Tableofcontents$"];
drText = dsSOW.Tables["Tableofcontents" + "$"].Select("Mappingcode is NULL"); 
if (drText.Length > 0)
{ 
foreach (DataRow drItem in drText)
{ 
string ss = drItem.ItemArray[1].ToString();
  string ss1 = drItem.ItemArray[0].ToString(); 
if (ss1 != string.Empty) 
{ 
TreeNode node = new TreeNode(ss, ss1);
node.PopulateOnDemand = false; 
TVContent.Nodes.Add(node); 
PopulateNode(node);
}
} 
} 
} 
protected void PopulateNode(TreeNode node1)
{ 
decimal order = Convert.ToDecimal(node1.Value);
drText = dsSOW.Tables["Tableofcontents" + "$"].Select("Mappingcode='" + order + "'");
if (drText.Length > 0) 
{
foreach (DataRow drItem in drText) 
{ string ss = drItem.ItemArray[1].ToString(); 
string ss1 = drItem.ItemArray[0].ToString(); 
TreeNode node = new TreeNode(ss, ss1);
DataRow[] drText1 = dsSOW.Tables["Content" + "$"].Select("contentcode='" + ss1 + "'"); 
if (drText1.Length > 0)
{ 
foreach (DataRow drItem1 in drText1)
{ 
txtArea.Text = txtArea.Text + drItem1.ItemArray[1].ToString();
} 
}
node1.ChildNodes.Add(node); 
snode = node.Value;
if (snode != string.Empty) 
{
drText = dsSOW.Tables["Tableofcontents$"].Select("Mappingcode='" + snode + "'");
if (drText.Length > 0)
{ 
PopulateNode(node);
}
}
}
} 
TVContent.Attributes.Add("OnClick", "OnTreeClick(event)"); 
}
 

 
On implementing this code, I am getting the descriptions about the nodes in page load itself.. I want that to appear only after i click the nodes. And i fetch values for description from a dataset.
 
Please Help.!
Thanku.!