ErrorHandling.cs

using System;
using System.Collections.ObjectModel;
using System.Diagnostics;
using System.Reactive;
using System.Reactive.Disposables;
using System.Reactive.Linq;
using System.Threading.Tasks;
using ReactiveUI;
using RxUIForms.Models;
using Xamvvm;

namespace RxUIForms.ViewModels
{
    /* Omitted */

    public class HomePageViewModel : BasePageViewModel
    {   
        private async Task ShowAlert()
        {
            // Natrually, this is silly, but it demonstrates how to use Merged Observables to 
            // handle errors elegantly. 
            try
            {
                throw new NotImplementedException("This is a fake error to demonstrate the alert");
            }
            catch(Exception ex)
            {
                await Observable.Throw<Unit>(ex);
            }
        }
        
        /* Omitted */
        
        private void Initialize()
        {
            // Error Handling
            Observable.Merge(this.ThrownExceptions, SelectItemCommand.ThrownExceptions, ShowAlertCommand.ThrownExceptions, ShowActionSheetCommand.ThrownExceptions)
                      .Throttle(TimeSpan.FromMilliseconds(250), RxApp.MainThreadScheduler)
                      .Do((obj) => Debug.WriteLine($"[{obj.Source}] Error = {obj}"))
                      .Subscribe(async ex =>
            {
                var response = await Interactions.Errors.Handle(ex);

                if (response == ErrorRecoveryOption.Retry)
                {
                    // TODO: If response is true, the user wants to "retry" the action. 
                    // Do something here to attempt the action again
                }
                else
                {
                    // TODO: If response is false, the user has canceled the attempted action
                    // So perform an action here that makes sense; we may want to naviagte to 
                    // a previous page or just sit idle
                }

            }).DisposeWith(SubscriptionDisposables);
        }
    }
}