/// <summary>
        /// Creates a new Customer
        /// </summary>
        private void create( )
        {
            try
            {
                if (string.IsNullOrEmpty(this.Address) ||
                    string.IsNullOrEmpty(this.FirstName) ||
                    string.IsNullOrEmpty(this.LastName))
                {
                    throw new Exception("Nicht alle Werte eingegeben");
                }
                DateTime bd;
                try
                {
                    bd = DateTime.Parse(BirthDate);
                }
                catch (Exception e)
                {
                    throw new Exception("Datumsformat nicht korrekt!");
                }

                Customer     c   = CustomerManager.CreateCustomer("", this.FirstName, this.LastName, bd, this.Address);
                UserInfoView uiv = new UserInfoView(c);
                uiv.ShowDialog();
            }
            catch (Exception ex)
            {
                ExceptionHelper.Handle(ex);
            }
        }