Bug 38851 - [Forms] Unexpected Listview deselection behavior (XAML)
Summary: [Forms] Unexpected Listview deselection behavior (XAML)
Alias: None
Product: Forms
Classification: Xamarin
Component: Forms ()
Version: 2.0.0
Hardware: Macintosh Mac OS
: Normal normal
Target Milestone: ---
Assignee: Bugzilla
Depends on:
Reported: 2016-02-17 16:00 UTC by Matthew Regul
Modified: 2016-02-17 18:40 UTC (History)
8 users (show)

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

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Description Matthew Regul 2016-02-17 16:00:44 UTC
== Overview: =================================
Calling `List.SelectedItem = null` does not always clear the selected list item, multiple calls/clicks may be required.

Possible that this is a result of having the 'clear' nested inside of an If Statement?
(as seen here - https://gist.github.com/mattregul/c1356a808a20b1a2c734#file-testpage-xaml-cs-L56-L72)

When calling `List.SelectedItem = null` unnested, at the end of OnItemSelected(), the list item will clear as expected.
(as seen here - https://gist.github.com/mattregul/c1356a808a20b1a2c734#file-testpage-xaml-cs-L91-L108)

== Steps to Reproduce: =======================
Using Sample App - https://dl.dropboxusercontent.com/u/62849286/Bugs/BugListviewDeselect/ListviewSelectTest.zip

** The TOP listview is where the bug resides
** The BOTTOM listview functions as expected

[TOP - Bugged Listview]
1. Load the app
2. Select one of the names from the TOP listview (name #1)
3. Click on a different name (#2)
4. Click on the same name again (#2)
 - Note that same list item is still visually selected, but according to the code (and the Application Output), if the same record is clicked as the previous, the current item should be unselected.  
 - Note the app output, Deselection was attempted, but did not work
5. Clicking on the same name (#2), again... will now clear the selection correctly
6. Once cleared, clicking the same name (#2) again will clear the selection immediately
7. Clicking on a different name starts the whole process over again

[BOTTOM - Working Listview]
1. Load the app (no need to reload if already running)
2. Select one of the names from the BOTTOM listview (name #1)
 - Note that the name is deselected immediately
3. Select another name, which will also be deselected immeditly

- Android (best example)- http://screencast.com/t/eRsxWHtMMJp
- iOS - http://screencast.com/t/6izlastuaQ2M

[Code Snips]
- Clears selection when previous record is selected, but requires *several* clicks
 o https://gist.github.com/mattregul/c1356a808a20b1a2c734#file-testpage-xaml-cs-L56-L72

- Clears when any record is selected
 o https://gist.github.com/mattregul/c1356a808a20b1a2c734#file-testpage-xaml-cs-L91-L108

== Actual Results: ===========================
For unknown reasons, multiple calls of `List.SelectedItem = null` are required in some situations (possibly when nested?)

== Expected Results: =========================
Regardless of location in code, when `List.SelectedItem = null` is called, the selected item should be deselected

== Build Date & Platform: ====================
Xamarin Forms -
Version Info - https://gist.github.com/mattregul/c1356a808a20b1a2c734#file-version-info-cs