can't bind a viewmodel to a ResourceDictionary - xamarin.forms

Question

I am trying to bind my ViewModelBase in a ResourceDictionary so that I can call some of the properties to set the properties on my controls, for example I have a label and I want to set its color by one of the properties in my ViewModelBase...
Update: The ResourceDictionary resides in my styles folder and gets called on bootup, it does not reside in a page like so...
void LoadStyles()
{
if (IsASmallDevice())
{
MyResources.MergedDictionaries.Add(SmallDevicesStyle.SharedInstance);
}
else
{
MyResources.MergedDictionaries.Add(GeneralDevicesStyle.SharedInstance);
}
}
<?xml version="1.0" encoding="utf-8" ?>
<ResourceDictionary xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:d="http://xamarin.com/schemas/2014/forms/design"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:viewModels="clr-namespace:MyApp.ViewModels"
mc:Ignorable="d"
x:Class="MyApp.Styles.GeneralDevicesStyle">
<viewModels:ViewModelBase x:Key="BaseView"/>
<OnIdiom x:TypeArguments="x:Double" Tablet="30" Phone="10" x:Key="PageSpacing" />
<OnIdiom x:TypeArguments="Thickness" Tablet="10" Phone="10" x:Key="PagePadding" />
<Style TargetType="Label" x:Key="LabelStyle1">
<Setter Property="FontSize">
<Setter.Value>
<OnIdiom x:TypeArguments="x:Double" Phone="15" Tablet="15"/>
</Setter.Value>
</Setter>
<Setter Property="HorizontalOptions" Value="FillAndExpand" />
<Setter Property="VerticalOptions" Value="FillAndExpand" />
<Setter Property="BackgroundColor" Value="{Binding DefaultLabelColor}" />
</Style>
</ResourceDictionary>
public class ViewModelBase : BaseViewModel
{
sting BackGroundColor = "aqua";
public string DefaultBackGroundColor { get return BackGroundColor; }
}
So my question is, How can I bind my ViewModelBase in my ResourceDictionary so that I can access the properties/Methods that reside in the ViewModelBase?

Answer 1

You need to set the BindingContext for Label.
ViewModelBase:
public class ViewModelBase
{
//public string DefaultBackGroundColor { get; set; } = "Aqua";
private string BackGroundColor = "Aqua";
public string DefaultBackGroundColor
{
get { return BackGroundColor; }
}
}
Xaml:
<ContentPage.Resources>
<ResourceDictionary>
<viewModels:ViewModelBase x:Key="BaseView" />
</ResourceDictionary>
<Style TargetType="Label">
<Setter Property="BackgroundColor" Value="{Binding DefaultBackGroundColor}" />
<Setter Property="BindingContext" Value="{StaticResource BaseView}"></Setter>
</Style>
</ContentPage.Resources>
<ContentPage.Content>
<StackLayout>
<Label
HorizontalOptions="CenterAndExpand"
Text="Welcome to Xamarin.Forms!"
VerticalOptions="CenterAndExpand" />
</StackLayout>
</ContentPage.Content>