Merge branch 'entity-page-change-fix' into entities-or2018

src/app/+item-page/full/full-item-page.component.ts

-import { ChangeDetectionStrategy, Component, OnInit } from '@angular/core';
+import { ChangeDetectionStrategy, ChangeDetectorRef, Component, OnInit } from '@angular/core';
 import { ActivatedRoute } from '@angular/router';
 
 import { Observable } from 'rxjs/Observable';
@@ -14,6 +14,7 @@ import { MetadataService } from '../../core/metadata/metadata.service';
 
 import { fadeInOut } from '../../shared/animations/fade';
 import { hasValue } from '../../shared/empty.util';
+import { BehaviorSubject } from 'rxjs/BehaviorSubject';
 
 /**
  * This component renders a simple item page.
@@ -30,7 +31,7 @@ import { hasValue } from '../../shared/empty.util';
 })
 export class FullItemPageComponent extends ItemPageComponent implements OnInit {
 
-  itemRDObs: Observable<RemoteData<Item>>;
+  itemRDObs: BehaviorSubject<RemoteData<Item>>;
 
   metadataObs: Observable<Metadatum[]>;
 

src/app/+item-page/simple/item-page.component.ts

-import { ChangeDetectionStrategy, Component, OnInit } from '@angular/core';
+import { ChangeDetectionStrategy, ChangeDetectorRef, Component, OnInit } from '@angular/core';
 import { ActivatedRoute } from '@angular/router';
 
 import { Observable } from 'rxjs/Observable';
@@ -13,6 +13,7 @@ import { MetadataService } from '../../core/metadata/metadata.service';
 import { fadeInOut } from '../../shared/animations/fade';
 import { hasValue } from '../../shared/empty.util';
 import * as viewMode from '../../shared/view-mode';
+import { BehaviorSubject } from 'rxjs/BehaviorSubject';
 
 /**
  * This component renders a simple item page.
@@ -32,16 +33,16 @@ export class ItemPageComponent implements OnInit {
 
   private sub: any;
 
-  itemRDObs: Observable<RemoteData<Item>>;
-
   thumbnailObs: Observable<Bitstream>;
 
+  itemRDObs?: BehaviorSubject<RemoteData<Item>> = new BehaviorSubject(new RemoteData(true, true, false, null, null));
+
   ElementViewMode = viewMode.ElementViewMode;
 
   constructor(
     private route: ActivatedRoute,
     private items: ItemDataService,
-    private metadataService: MetadataService
+    private metadataService: MetadataService,
   ) {
 
   }
@@ -50,16 +51,16 @@ export class ItemPageComponent implements OnInit {
     this.sub = this.route.params.subscribe((params) => {
       this.initialize(params);
     });
+
   }
 
   initialize(params) {
     this.id = +params.id;
-    this.itemRDObs = this.items.findById(params.id);
+    this.items.findById(params.id).filter((rd) => hasValue(rd.payload)).first().subscribe((item) => this.itemRDObs.next(item));
     this.metadataService.processRemoteData(this.itemRDObs);
     this.thumbnailObs = this.itemRDObs
       .map((rd: RemoteData<Item>) => rd.payload)
       .filter((item: Item) => hasValue(item))
       .flatMap((item: Item) => item.getThumbnail());
   }
-
 }

src/app/shared/view-mode.ts

 export enum SetViewMode {
-  List,
-  Grid
+  List = 'list',
+  Grid = 'grid'
 }
 
 export enum ElementViewMode {