Global Resources problem in Xamarin projects

Today I spent a lot of time to understand why my style doesn’t work.

<Application xmlns="https://xamarin.com/schemas/2014/forms" 
             xmlns:x="https://schemas.microsoft.com/winfx/2009/xaml" 
             x:Class="myProject.App">
    <Application.Resources>
        <ResourceDictionary>
            <Style x:Key="WarmGreyLine" TargetType="BoxView">
                <Setter Property="HeightRequest" Value="1" />
                <Setter Property="HorizontalOptions" Value="Fill" />
                <Setter Property="Color" Value="#EEE9E5" />
                <Setter Property="Margin" Value="0,10,0,10" />
            </Style>
        </ResourceDictionary>
    </Application.Resources>
</Application>

I followed a video about it on Xamarin University. Everything was the same. They say you can copy your style from a ContentPage.Resources and page in the Application.Resources section

    <ContentPage.Resources>
        <ResourceDictionary>
            <Style x:Key="WarmGreyLine" TargetType="BoxView">
                <Setter Property="HeightRequest" Value="1" />
                <Setter Property="HorizontalOptions" Value="Fill" />
                <Setter Property="Color" Value="#EEE9E5" />
                <Setter Property="Margin" Value="0,10,0,10" />
            </Style>
        </ResourceDictionary>
    </ContentPage.Resources>

The XAML is correct but if you execute the code you receive an error like:

Inner Exception: Position 38:14. StaticResource not found for key WarmGreyLine Message: Exception has been thrown by the target of an invocation.

The Solution

The is a little thing in the video they forgot to say!

In the App.xaml.cs you have to call InitializeComponent();

namespace myInventories
{
    public partial class App : Application
    {
        public App()
        {
            InitializeComponent();
        }
    }
} 

Happy coding!