treeview data to database

protected void btn1_Click(object sender, EventArgs e) 
{ 
     SqlConnection con = new SqlConnection("Data Source=GAYATHRI\SQLEXPRESS;Initial      Catalog=VOY_SERVICES1;Integrated Security=True"); con.Open();
 
    foreach (TreeNode tnode in TreeView1.CheckedNodes)
    {
        if (tnode.Checked == true)
        {
 
            string strTreeValue;
            strTreeValue = tnode.Value;
            SqlCommand com = new SqlCommand("insert into treeview_select(subdisease_name) values(@name)", con);
 
            com.Parameters.AddWithValue("@name", strTreeValue);
            com.ExecuteNonQuery();
            com.Dispose();
            //con.Close(); if connection is closed, the command will be executed only once!
        }
    }
con.Close();
com = Nothing;
con = Nothing;
}