Bug 60846 - Picker Itemsource of IEnumerable<Real object> not working
Summary: Picker Itemsource of IEnumerable<Real object> not working
Status: NEEDINFO
Alias: None
Product: Forms
Classification: Xamarin
Component: Forms ()
Version: 2.5.0
Hardware: PC Windows
: --- normal
Target Milestone: ---
Assignee: Bugzilla
URL:
Depends on:
Blocks:
 
Reported: 2017-11-24 09:03 UTC by Joacim Wall
Modified: 2017-11-29 07:50 UTC (History)
2 users (show)

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

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Status:
NEEDINFO

Description Joacim Wall 2017-11-24 09:03:23 UTC
Hi Xamarin picker crash on SelectedItemChange event. 

This happened only for realm objects I filed a report on the realm forum but the think it's in the control. 

Please se this.

https://forums.realm.io/t/picker-itemsource-of-ienumerable-real-object-not-working/716

Code to reproduce it.

https://www.dropbox.com/s/h8h9z87gkm1wap5/QuickJournal.zip?dl=0
Comment 1 Paul DiPietro [MSFT] 2017-11-28 22:43:16 UTC
I'm reading the comments in the first link's discussion and it looks as if your issue has been resolved. Can you confirm?
Comment 2 Joacim Wall 2017-11-29 07:44:14 UTC
it's has not been resolved there are A workaround. The Picker has more flows.

Fill a Picker with object with id and name throw viewmodel and observibleCollection using itemsource and selecteditem.

1. Select one of them 
2. Navigate to new page and edit name off the object in the picker thow 
   binded entry.
   Navigation.PushAsync(new Views.Phone.CustomerPage(new 
   ViewModels.CustomerPageViewModel(SelectedCustomer)));
3. Edit Name of the selected object
4. Save and Navigation.PopAsync(true);
5. I see that the SelectedCustomer is updated but not the picker.
when you get back to the previous page the picker is not updated but the selectedCustomer is.If you change the picker to i listview it works.  

My workaround for this is in the codebehind of the firstpage in 
protected override void OnAppearing() .. 
(BindingContext as ViewModels.StartPageViewModel).InitPickers();

public async void InitPickers()
{
string selectedCustomerId = null;
if (SelectedCustomer != null)
{
selectedCustomerId = SelectedCustomer.CustomerId;
Customers.Clear();
Customers = CustomerRepository.GetAllCustomers();
await System.Threading.Tasks.Task.Delay(250);
SelectedCustomer = Customers.FirstOrDefault(x => x.CustomerId == selectedCustomerId);
}
else /
Customers = CustomerRepository.GetAllCustomers();
}

The solution is await line, thinks it's need to load gui before i can set selected item. The strange thing is if i replace picker with a listview it works out of the box on PopAsync.
Comment 3 Joacim Wall 2017-11-29 07:50:37 UTC
For your info i use net standard 2.0 and problem is on Iphone 8 IOS 11.1 simulator.