Service class for the store category model.
Inheritance: StoreServiceBase
        protected void btnRetrieveOrganization_Click( object sender, EventArgs e )
        {
            // get organizations
            string errorMessage = string.Empty;

            OrganizationService organizationService = new OrganizationService();
            List<Organization> organizations = organizationService.GetOrganizations(txtUsername.Text, txtPassword.Text, out errorMessage).ToList();

            switch ( organizations.Count )
            {
                case 1:
                    SetOrganization(organizations.First());
                    break;
                case 0:
                    ProcessNoResults();
                    break;
                default:
                    ProcessMultipleOrganizations(organizations);
                    break;
            }
        }