Bug 27229 - Failure with SetBinding<TSource>
Summary: Failure with SetBinding<TSource>
Status: RESOLVED FIXED
Alias: None
Product: Forms
Classification: Xamarin
Component: Forms ()
Version: 1.3.2
Hardware: PC Mac OS
: Normal normal
Target Milestone: ---
Assignee: Bugzilla
URL:
Depends on:
Blocks:
 
Reported: 2015-02-19 14:24 UTC by scott
Modified: 2015-06-29 08:14 UTC (History)
5 users (show)

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

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Status:
RESOLVED FIXED

Description scott 2015-02-19 14:24:19 UTC
I'm using SetBinding<TSource> from the BindableObjectExtensions class, and seeing a case where binding updates don't happen.

I can actually see that it doesn't appear the infrastructure ever wires up an event handler for the property changed notification.

If I instead bind with: BindableObjectExtensions.SetBinding(this BindableObject self, BindableProperty targetProperty, string path, BindingMode mode = BindingMode.Default, IValueConverter converter = null, string stringFormat = null), 

everything works fine.

It appears that perhaps the Binding.GetBindingPath method is not correctly determining a binding path for my case.

Doesn't work:
            var totalCheckTime = new TextCell { Text = "Total Check Time" };
            totalCheckTime.SetBinding<HealthCheckPageModel>(TextCell.DetailProperty, vm => ((AsyncCommand<HealthCheck>)vm.DoHealthCheckCommand).Execution.Result.TotalTiming);
     
Works fine:
            var totalCheckTime = new TextCell { Text = "Total Check Time" };

            totalCheckTime.SetBinding(TextCell.DetailProperty,"DoHealthCheckCommand.Execution.Result.TotalTiming");

I'm attempting to bind to a member of my view model that is declared like: 

 public IAsyncCommand DoHealthCheckCommand { get; private set; }

with initialization: 
 DoHealthCheckCommand = new AsyncCommand<HealthCheck>(token => this.healthCheckService.Get(token));

based on the ideas and writing here: https://msdn.microsoft.com/en-us/magazine/dn630647.aspx

   public class AsyncCommand<TResult> : AsyncCommandBase, INotifyPropertyChanged
    {
...
  public NotifyTaskCompletion<TResult> Execution...
...
}