One of the aspects of XAML that is often misunderstood is that of ambient properties. Probably the best example of this is being able to set the foreground colour on a Page in UWP and for the foreground color to be set on every element on the page. Unfortunately this doesn’t seem to be something that’s available in Xamarin.Forms, which lead me to wonder how hard it would be to implement.
The implementation would be slightly different from UWP which uses the AmbientAttribute. Instead I’ll create an attached property which can be set on any element. The ForeColor will be then set on each child element, unless the TextColor is explcitly set on an element.
For example the following XAML
<StackLayout
vsm:Ambient.ForeColor=”Blue”>
<Label Text=”Hello World – Blue!” />
<Label TextColor=”Red”
Text=”Hello World – Red!” />
</StackLayout>
would generate the following output
Over the next couple of days the Ambient.ForeColor property will be added to BuildIt.Forms, which also includes the VisualStateManager I described in my past two posts (here and here).