What is XAML generated break on unhandled exception and app.g.i.cs file

Question

I am new to windows app development. I am trying to execute a solution on my local machine using x64 platform. But whenever I execute a Buttom_Click event I am getting this exception

#if DEBUG && !DISABLE_XAML_GENERATED_BREAK_ON_UNHANDLED_EXCEPTION UnhandledException += (sender, e) => { if (global::System.Diagnostics.Debugger.IsAttached) global::System.Diagnostics.Debugger.Break(); }; #endif

in App.g.i.cs file.

I am getting this exception when debugger hits the variable 'icon' below

 private async void Button_Click(object sender, RoutedEventArgs e) { RootObject myWeather = await OpenWeatherMapProxy.GetWeather(20.0,30.0); string icon = String.Format("ms-appx:///Assets/Weather/{0}.png", myWeather.weather[0].icon); ResultImage.Source = new BitmapImage(new Uri(icon, UriKind.Absolute)); ResultTextBlock.Text = myWeather.name + " - " + ((int)myWeather.main.temp).ToString() + " - " + myWeather.weather[0].description; }

It would be helpful if anyone can explain how to get rid of this exception and what is App.g.i.cs file.

It is null at 'string icon =....' but debugger is not even hitting the line 'Result image = ...' and exception is being thrown — Coder221
– Coder221, Commented Feb 14, 2016 at 14:42

Dennis Ameling · Accepted Answer · 2017-07-03 02:00:22Z

App.g.i.cs is an auto genearated file, and its breaking at that location because you haven't handled the exception properly in your code.

private async void Button_Click(object sender, RoutedEventArgs e) { try{ RootObject myWeather = await OpenWeatherMapProxy.GetWeather(20.0,30.0); string icon = String.Format("ms-appx:///Assets/Weather/{0}.png", myWeather.weather[0].icon); ResultImage.Source = new BitmapImage(new Uri(icon, UriKind.Absolute)); ResultTextBlock.Text = myWeather.name + " - " + ((int)myWeather.main.temp).ToString() + " - " + myWeather.weather[0].description; } catch(Exception ex) { Debug.WriteLine(ex.Message); Debug.WriteLine(ex.StackTrace); } }

Go to the Output window when the application is running and go through the exception detail, you might find the answer.

Mostlikely exception is causeded by myWeather or myWeather.weather[0] being null because OpenWeatherMapProxy.GetWeather failed to fetch the data.

Appreciate your reply, now it is clear what should I be doing to handle correctly. I did as you told and when I combined the results of exceptions in output window, it boils down to this " Object reference not set to an instance of an object at TestWeather.MainPage.<Button_Click>d__1.MoveNext() " But I never implemented MoveNext() method and it is no where to be found in solution as well.
at TestWeather.MainPage.<Button_Click>d__1.MoveNext() That is the entire stacktrace.
thats not the stack trace... it gives the whole path of the calls.
An alternate solution is to turn on first-chance exceptions in the Debug Settings; that obviates the need to add try/catch throughout your code.

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