private void ListContacts()
        {
            string token = (string)Session["token"];

            txtCompanyName.Text = "";
            txtContactName.Text = "";
            txtContactTypeID.Text = "";

            ContactManager contactManager = new ContactManager();

            ContactGetHeader contactHeader = contactManager.GetContacts(token);

            DisplayContacts(contactHeader);
        }
        protected void btnCreateContact_Click(object sender, EventArgs e)
        {
            string contactName = txtContactName.Text;
            string companyName = txtCompanyName.Text;
            int contactTypeID = Int32.Parse(txtContactTypeID.Text);

            string token = (string)Session["token"];

            ContactManager contactManager = new ContactManager();

            string result = contactManager.CreateContact(contactName, companyName, "", "", contactTypeID, token);
                       
            ListContacts();

        }
        protected void btnDeleteContact_Click(object sender, EventArgs e)
        {
            string token = (string)Session["token"];
            ContactManager contactManager = new ContactManager();
            string result = contactManager.DeleteContact(ListBoxContacts.SelectedItem.Value.ToString(), token);

            ListContacts();
        }
        protected void btnUpdateContact_Click(object sender, EventArgs e)
        {
            string token = (string)Session["token"];
            ContactManager contactManager = new ContactManager();
            string result = contactManager.UpdateContact(ListBoxContacts.SelectedItem.Value.ToString(), 
                txtContactName.Text, txtCompanyName.Text, "", "", 
                Int32.Parse(txtContactTypeID.Text), token);

            ListContacts();
        }