#328432 Fix error in checking for ability to unregister and add error for unexpected count of updated registrations when changing date vote.

app/events/event-details/event-details.component.ts

@@ -202,7 +202,7 @@ export class EventDetailsComponent implements OnInit {
     }
 
     canUnregister() {
-        return this.alreadyRegistered && !this.isPastEvent && this.event.OpenForRegistration && !this.event.RegistrationCompleted;
+        return this.event && this.alreadyRegistered && !this.isPastEvent && this.event.OpenForRegistration && !this.event.RegistrationCompleted;
     }
 
     unregister() {

app/services/event-registrations.service.ts

@@ -54,7 +54,13 @@ export class EventRegistrationsService {
 
     updateChoices(eventId: string, userId: string, newChoices: string[]) {
         let filter = { EventId: eventId, UserId: userId };
-        return this._data.update({ Choices: newChoices }, filter);
+        return this._data.update({ Choices: newChoices }, filter)
+            .then(resp => {
+                if (resp.result !== 1) {
+                    return Promise.reject({ message: 'Unexpected number of updated records - check back end' });
+                }
+                return resp;
+            });
     }
 
     create(eventId: string, userId: string, dateChoices: string[]) {