ButtonDisabledStatesGallery.xaml

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
			xmlns:windowsSpecific="clr-namespace:Xamarin.Forms.PlatformConfiguration.WindowsSpecific;assembly=Xamarin.Forms.Core"
			xmlns:androidSpecific="clr-namespace:Xamarin.Forms.PlatformConfiguration.AndroidSpecific;assembly=Xamarin.Forms.Core"
			xmlns:iosSpecific="clr-namespace:Xamarin.Forms.PlatformConfiguration.iOSSpecific;assembly=Xamarin.Forms.Core"
			x:Class="Xamarin.Forms.Controls.GalleryPages.VisualStateManagerGalleries.ButtonDisabledStatesGallery"
			Title="Button Disabled States Gallery">
	
	<ContentPage.Resources>
		<ResourceDictionary>

			<Style TargetType="Button" x:Key="CustomDisabledState">
				<Setter Property="VisualStateManager.VisualStateGroups">
					<VisualStateGroupList>
						<VisualStateGroup x:Name="CommonStates">
							<VisualState x:Name="Normal" />
							<!-- Because we're creating our own PointerOver state here, the Forms VSM will override
							the Windows VSM for UWP. So this button won't display the native PointerOver behavior. 
							If we remove this next line, the usual PointerOver behavior will be restored. -->
							<VisualState x:Name="PointerOver" />
							<VisualState x:Name="Disabled">
								<VisualState.Setters>
									<Setter Property="TextColor" Value="Red" />
									<Setter Property="BackgroundColor" Value="Purple" />
								</VisualState.Setters>
							</VisualState>
						</VisualStateGroup>
					</VisualStateGroupList>
				</Setter>
			</Style>

			<Style TargetType="Button" x:Key="DefaultInInitialState">
				<Setter Property="VisualStateManager.VisualStateGroups">
					<VisualStateGroupList>
						<VisualStateGroup x:Name="CommonStates">
							<VisualState x:Name="Normal" />
							<VisualState x:Name="Disabled">
								<VisualState.Setters>
									<Setter Property="TextColor" Value="Green" />
									<Setter Property="BackgroundColor" Value="Black" />
								</VisualState.Setters>
							</VisualState>
						</VisualStateGroup>
					</VisualStateGroupList>
				</Setter>
			</Style>

		</ResourceDictionary>
	</ContentPage.Resources>


	<ContentPage.Content>
		<ScrollView VerticalOptions="Fill" HorizontalOptions="Fill">
			<StackLayout>

				<!-- Not using the VSM at all; should exhibit pre-VSM default behavior -->
				<Label Text="The Button below uses the current XF defaults; when IsEnabled is false, it uses the default native colors for the control. (Legacy Color Behavior)"/>
				<Button Text="Button" x:Name="Button0" TextColor="Blue" BackgroundColor="Bisque" />
				<Button Text="Toggle IsEnabled" x:Name="Button0_Toggle" Clicked="Button0_Toggle_OnClicked" />

				<!-- Legacy Color Behavior turned off by the PlatformSpecific; ignores states entirely and uses 
				whatever colors are manually set for it -->
				<Label Text="The Button below has the Legacy Color Behavior disabled; it will stick with whatever colors are set, regardless of state"/>
				<Button Text="Button" x:Name="Button1" TextColor="Blue" BackgroundColor="Bisque"
						androidSpecific:VisualElement.IsLegacyColorModeEnabled="False"
						iosSpecific:VisualElement.IsLegacyColorModeEnabled="False"
						windowsSpecific:VisualElement.IsLegacyColorModeEnabled="False"
						/>
				<Button Text="Toggle IsEnabled" x:Name="Button1_Toggle" Clicked="Button1_Toggle_OnClicked" />

				<!-- Disabled colors fully managed by the VSM -->
				<Label Text="The Button below uses the VSM to customize the colors for the disabled state." />
				<Button Text="Button" x:Name="Button2" Style="{StaticResource CustomDisabledState}" TextColor="Green" 
				   BackgroundColor="Beige" />
				<Button Text="Toggle IsEnabled" x:Name="Button2_Toggle" Clicked="Button2_Toggle_OnClicked" />

				<!-- This section verifies that the default colors for an entry's text and placeholder are cached and can be reverted to -->
				<Label Text="This Button uses Color.Default for the intial text/background, and colors from the VSM when disabled."/>
				<Button Text="Button" x:Name="Button3" Style="{StaticResource DefaultInInitialState}" TextColor="Default" 
					BackgroundColor="Default" />
				<Button Text="Toggle IsEnabled" x:Name="Button3_Toggle" Clicked="Button3_Toggle_OnClicked" />
			</StackLayout>
		</ScrollView>
	</ContentPage.Content>
</ContentPage>