Saving Checkbox Values from TreeView to Database

See more:

C#

ASP.NET

I am new to using C# but I am working with code that someone has designed a dynamically populated asp:treeview. I need to be able to retrieve the values from the checkboxes and save them to the database. Here is a sample of the front end code:

<asp:treeview id="tvCategories" xmlns:asp="#unknown">
   Font-Names="Arial" ForeColor="Blue"
   EnableClientScript="true"
   PopulateNodesFromClient="true" 
   OnTreeNodePopulate="PopulateNode" runat="server">
   
   <asp:treenode text="Product Categories"> 
      SelectAction="SelectExpand" 
      PopulateOnDemand="true" />
   </asp:treenode>
</asp:treeview></asp:treenode></asp:treeview>

Here is how the sub catagory is populated:

void PopulateSubCategories(TreeNode node)
{
  // Query for the product categories. These are the values
  // for the second-level nodes.
  DataSet ResultSet = RunQuery("Select ProductCategoryId, Category From ProductCategory"
                               + " Where ParentCategoryId=" + node.Value);
  // Create the second-level nodes.
  if (ResultSet.Tables.Count > 0)
  {
    // Iterate through and create a new node for each row in the query results.
    // Notice that the query results are stored in the table of the DataSet.
    foreach (DataRow row in ResultSet.Tables[0].Rows)
    {
      // Create the new node. Notice that the CategoryId is stored in the Value property 
      // of the node. This will make querying for items in a specific category easier when
      // the third-level nodes are created. 
      TreeNode newNode = new TreeNode();
      newNode.Text = row["Category"].ToString();
      newNode.Value = row["ProductCategoryId"].ToString();
      // Set the PopulateOnDemand property to true so that the child nodes can be 
      // dynamically populated.
      newNode.PopulateOnDemand = true;
      // Set additional properties for the node.
      newNode.SelectAction = TreeNodeSelectAction.Expand;
      newNode.ShowCheckBox = true;
      // Add the new node to the ChildNodes collection of the parent node.
      node.ChildNodes.Add(newNode);
    }
  }
}

I am attempting to save it as a normal checkbox but ran into trouble. Any assistance would be highly appreciated

[Modified: others added the pre tags. Fixed the tabbing.]