Bug 31088 - FontSize = Font.SystemFontOfSize(NamedSize.Large).FontSize; // crashes in WP
Summary: FontSize = Font.SystemFontOfSize(NamedSize.Large).FontSize; // crashes in WP
Alias: None
Product: Forms
Classification: Xamarin
Component: Windows ()
Version: 1.4.2
Hardware: PC Windows
: --- normal
Target Milestone: ---
Assignee: Bugzilla
Depends on:
Reported: 2015-06-13 11:25 UTC by Niels
Modified: 2015-06-16 14:15 UTC (History)
2 users (show)

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

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Description Niels 2015-06-13 11:25:57 UTC
I got an "obsolete" warning in VS on the following line of code:

Font = Font.SystemFontOfSize(NamedSize.Large),

So I changed it to:

FontSize = Font.SystemFontOfSize(NamedSize.Large).FontSize

This caused the following error on Windows Phone and prevented a page from loading:

{System.ArgumentOutOfRangeException: Specified argument was out of the range of valid values.
   at Xamarin.Forms.Platform.WinPhone.FontExtensions.ApplyFont(TextBlock self, Font font)
   at Xamarin.Forms.Platform.WinPhone.LabelRenderer.UpdateFont(TextBlock textBlock)
   at Xamarin.Forms.Platform.WinPhone.LabelRenderer.OnElementChanged(ElementChangedEventArgs`1 e)
   at Xamarin.Forms.Platform.WinPhone.VisualElementRenderer`2.SetElement(VisualElement element)
   at Xamarin.Forms.Platform.WinPhone.RendererFactory.GetRenderer(VisualElement view)
   at Xamarin.Forms.Platform.WinPhone.VisualElementPackager.HandleChildAdded(Object sender, ElementEventArgs e)
   at Xamarin.Forms.Element.OnChildAdded(Element child)
   at Xamarin.Forms.Layout.OnInternalAdded(View view)
   at Xamarin.Forms.Layout.InternalChildrenOnCollectionChanged(Object sender, NotifyCollectionChangedEventArgs e)
   at System.Collections.Specialized.NotifyCollectionChangedEventHandler.Invoke(Object sender, NotifyCollectionChangedEventArgs e)
   at System.Collections.ObjectModel.ObservableCollection`1.OnCollectionChanged(NotifyCollectionChangedEventArgs e)
   at System.Collections.ObjectModel.ObservableCollection`1.InsertItem(Int32 index, T item)
   at System.Collections.ObjectModel.Collection`1.Add(T item)
   at Xamarin.Forms.ObservableWrapper`2.Add(TRestrict item)
   at FormsApp.Pages.ResultsFilterPage.<SetFilter>d__5.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.GetResult()
   at FormsApp.Pages.ResultsFilterPage.<ResultsFilterPage_Appearing>d__0.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.AsyncMethodBuilderCore.<ThrowAsync>b__3(Object state)}
Comment 1 Stephane Delcroix 2015-06-15 04:44:29 UTC
could you try this as workaround ?

    FontSize = Device.GetNamedSize (NamedSize.Large, label);
Comment 2 Jason Smith [MSFT] 2015-06-16 13:39:21 UTC
The workaround Stephane posted is the correct workaround. Unfortunately the code you posted could not be made to work without a behavioral change.
Comment 3 Niels 2015-06-16 14:15:45 UTC
This works, thanks! Maybe it is possible to throw an error on my previous code, because the page doesn't load without breaking or anything. I spent over an hour to search for the cause.