Adding customer into program
<p>I want my program to know that a new customer has been added i dont kow how to make the links between my CustomerManager class and my Form classes, I have already done the code which is needed, look here</p>

<p>Form 1</p>

<pre><code>if (customerframe.ShowDialog() == DialogResult.OK) //if button OK is clicked then value will be inserted
            {
                listviewitem = new ListViewItem("1");
                listviewitem.SubItems.Add(customerframe.firstName);
                listviewitem.SubItems.Add(customerframe.lastName);
                listviewitem.SubItems.Add(customerframe.zipcode);
                //there will be more here later

               this.listView1.Items.Add();
</code></pre>

<p>Form2</p>

<pre><code>        private void btnOk_Click(object sender, EventArgs e)
                {
                    MainForm main = new MainForm();
                    contact.FirstName = tbFirstName.Text;           
                    firstName = contact.FirstName;

                    contact.LastName = tbLastName.Text;            
                    lastName = contact.LastName;

//there will be more code here later as well
</code></pre>

<p>CustomerManager class</p>

<pre><code>class CustomerManager
    {
        private Customer CustomerIN;
        private List&lt;Customer&gt; customers = new List&lt;Customer&gt;();
        private int nrOfCustomers;
        private int id = 100;

        public CustomerManager()
        {
          throw new System.NotImplementedException();
        }

        public int Count
        {
            get
            {
              return nrOfCustomers;
            }
            set
            {
                foreach (Customer customer in customers)
                    nrOfCustomers++;
            }
        }

        public int GetNewID
        {
            get
            {
                return id;
            }
            set
            {
            }
        }

        public bool AddCustomer()
        {
                if (customers != null)
                {
                     foreach (Customer customer in customers)
                     {
                    customers.Add(customer);
                    CustomerIN.ID = id++;
                     }
                    return true;
                }
                else return false;
            }

        public bool ChangeCustomer()
        {
            throw new System.NotImplementedException();
        }

        public bool DeleteCustomer()
        {
            if (customers != null)
            {
                foreach (Customer customer in customers)
                {
                    customers.Remove(customer);
                }
                return true;
            }
            else return false;
        }

        public Customer GetCustomer()
        {
            throw new System.NotImplementedException();
        }

        public void TestValues()
        {
            throw new System.NotImplementedException();
        }
    }
}
</code></pre>

<p>I want the class above to interact with my forms in my program, because i think i have done my code very messy. How should i do</p>
