Bug 32534 - Selecting an item appears to remove it from collection
Summary: Selecting an item appears to remove it from collection
Status: VERIFIED FIXED
Alias: None
Product: Forms
Classification: Xamarin
Component: iOS ()
Version: 1.5.0
Hardware: PC Mac OS
: --- normal
Target Milestone: ---
Assignee: Rui Marinho
URL:
Depends on:
Blocks:
 
Reported: 2015-07-28 13:57 UTC by Cody Beyer (MSFT)
Modified: 2015-08-24 08:11 UTC (History)
3 users (show)

Tags: ac
Is this bug a regression?: ---
Last known good build:

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Status:
VERIFIED FIXED

Description Cody Beyer (MSFT) 2015-07-28 13:57:34 UTC
### Description 

The sample app has a list view, where if you select the item from the list view, and then return to the list, the item is no longer present

### Sample

https://www.dropbox.com/s/g8y2etsgkzcn7u4/ModifiedRestaurantGuide.zip?dl=0

### Video

https://www.dropbox.com/s/zqjdc0atm3ag5v9/ListItemGoesAway.mov?dl=0

### Steps to Reproduce

1. Download sample
2. Deploy to iOS
3. Click on item in list view
4. Click back nav button

### Expected Results

When you click back, everything should look as it was originally 

### Actual Results

The item you clicked on is now not visible in the list

### More Details for Customer

When I disable using TrulyObservableCollection (or comment out the call to
OnCollectionChanged) -- things work in this demo app.

However, in our real app app code we do no see updates to the ListView's
ViewCell contents with a standard ObservableCollection -- though tall
pieces of the ViewCell otherwise appear as expected.

### Versions

=== Xamarin Studio ===

Version 5.9.5 (build 6)
Installation UUID: 14e9db9d-4a59-440f-8c5b-890f54ec8c58
Runtime:
	Mono 4.0.3 ((detached/e4f44c1)
	GTK+ 2.24.23 (Raleigh theme)

	Package version: 400030019

=== Apple Developer Tools ===

Xcode 6.4 (7720)
Build 6E35b

=== Xamarin.iOS ===

Version: 8.10.4.27 (Business Edition)
Hash: 7cf6633
Branch: master
Build date: 2015-07-21 16:27:35-0400

=== Xamarin.Android ===

Version: 5.1.5.3 (Business Edition)
Android SDK: /Users/codybeyer/Library/Developer/Xamarin/android-sdk-macosx
	Supported Android versions:
		2.3   (API level 10)
		4.0.3 (API level 15)
		4.2   (API level 17)
		4.3   (API level 18)
		4.4   (API level 19)
		5.0   (API level 21)
Java SDK: /usr
java version "1.7.0_71"
Java(TM) SE Runtime Environment (build 1.7.0_71-b14)
Java HotSpot(TM) 64-Bit Server VM (build 24.71-b01, mixed mode)

=== Xamarin Android Player ===

Version: Unknown version
Location: /Applications/Xamarin Android Player.app

=== Xamarin.Mac ===

Version: 2.0.2.102 (Business Edition)

=== Build Information ===

Release ID: 509050006
Git revision: c50b1022a6b36f9b2a55beb7814b87811d1dba52
Build date: 2015-07-16 18:13:13-04
Xamarin addins: 6571e3228ff9e432a98b468630ec5ffd35f2f6b3

=== Operating System ===

Mac OS X 10.10.4
Darwin Codys-Macintosh.router 14.4.0 Darwin Kernel Version 14.4.0
    Thu May 28 11:35:04 PDT 2015
    root:xnu-2782.30.5~1/RELEASE_X86_64 x86_64
Comment 1 Chris King 2015-07-29 13:45:29 UTC
See TruelyObservableCollection.ItemPropertyChanged line 43.

ObservableCollection is subclassed as TruelyObservableCollection such that if a *property* of one of it's elements changes (as opposed to an addition, removal, or replacement of an entire element) then it fires OnCollectionChanged and swaps the item for *itself*. This should be a no-op but instead XF removes the element.
Comment 2 Rui Marinho 2015-08-13 09:36:57 UTC
Should be fixed in 1.5.0-pre2
Comment 3 Parmendra Kumar 2015-08-24 08:11:37 UTC
I have checked this issue with X.F 1.5.0-pre2 and now its working fine.


Hence closing this issue.


Environment info:
Xamarin Studio 5.9.5 (build 10)
Mono 4.0.3 ((detached/d6946b4)
GTK+ 2.24.23 (Raleigh theme)
Package version: 400030020
Xcode 6.2 (6776)
Xamarin.iOS : 8.10.4.46 (Enterprise Edition)
Xamarin.Android : 5.1.5.3 (Enterprise Edition)
Mac OS X 10.9.4