Xamarin Forms from Windows Phone 8.1(RT) - xaml exceptions - xaml

Question

I created app with Xamarin Forms for Windows Phone 8.1(RT). I updated XF to last version 2.3.4.231. My app in run to:
-windows phone 8.1 device
-windows phone 8.1 emulator
-mobile emulator 10.0.14393(x86)
It work is ok.
But when I running app to Windows 10 device(arm) I have many exception. I try different start pages and get mane exceptions(from xaml):
-Cannot assign property \"ColumnDefinitions\": Property does not exists, or is not assignable, or mismatching type between value and property"
-StaticResource not found for key ...
-An item with the same key has already been added
All these errors are related to xaml.
I do not use XamlCompilationOptions.Compile.
Last working version XF for my app 2.3.2.127
This small example:
I changed start page. I have exception:
-StaticResource not found for key StandardPadding
This is part of my page:
<StackLayout Padding="{StaticResource StandardPadding}">
My resource in App.xaml:
<Application.Resources>
<ResourceDictionary>
<Thickness x:Key="StandardPadding">16</Thickness>
</ResourceDictionary>
</Application.Resources>

Answer 1

I solved this problem. The error was in my xaml code. Xamarin Forms 2.3 not supported Windows OnPlatform in xaml. So I used this extension:
public class XOnPlatform<T> : OnPlatform<T>
{
public T Windows { get; set; }
public static implicit operator T(XOnPlatform<T> onPlatform)
{
if (Device.OS == TargetPlatform.Windows)
{
return onPlatform.Windows;
}
return (OnPlatform<T>)onPlatform;
}
}
I used this class in my xaml code. But in XF 2.3.4 Device.OS is obsolete. I removed XOnPlatform from my xaml code. I use OnPlatform in my xaml code.This is work. Bingo :)