Cannot add Flyout Footer in Xamarin forms app - visual-studio

Question

I have a xamarin forms application and I want to add a footer to the flyout menu. After reading the official documentation it should be straightforward, just adding a few lines into the AppShell.xaml like so:
<Shell.FlyoutFooterTemplate>
<DataTemplate>
<Label HeightRequest="300" BackgroundColor="Red"/>
</DataTemplate>
</Shell.FlyoutFooterTemplate>
This works perfectly fine when I tried it in a new project, but for some reason, it doesn't work in my current application giving this error:
Error XLS0415 The attachable property 'FlyoutFooterTemplate' was not found in type 'Shell'.
I tried to find the definition of FlyoutHeaderTemplate and I found this in Shell [from metadata] file:
[1]: https://i.stack.imgur.com/xqZub.png
public Shell();
...
public DataTemplate FlyoutHeaderTemplate { get; set; }
public FlyoutHeaderBehavior FlyoutHeaderBehavior { get; set; }
public object FlyoutHeader { get; set; }
There should be a similar definition for both, Header and Footer, but there is only one for the Header. The file cannot be edited and I was not able to locate it either. Any ideas why the definition for Footer is missing, how can I add it, or workarounds?
PS: Adding the footer from C# code doesn't work either and I tried to clean/rebuild and resetting both, PC and VS.

Answer 1

First, Confirm that you can add a simple Header:
<Shell.FlyoutHeader>
<Label Text="This is the header." />
</Shell.FlyoutFooter>
If that doesn't work, then you are doing something fundamentally wrong - post the code for the <Shell> XAML, within which you added those lines. Make sure you include those lines, to show where in the XAML they are. Make sure they are between <Shell> and </Shell>, but not nested inside some deeper node. For example, they musn't be inside a <StackLayout> or <ContentView> or other container - they must be direct children of the <Shell>.
Unless you are doing something fancy, you don't need a Template.
Try simply:
<Shell.FlyoutFooter>
<Label HeightRequest="300" BackgroundColor="Red"/>
</Shell.FlyoutFooter>
If 1) above works, but not 2), then your project is referencing an out-of-date version of Shell. Fixes:
A. Check that project's Xamarin.Forms nuget doesn't need an Update. (Solution / Manage Nugets.)
B. OR delete bin and obj folders. Then Rebuild Solution.
C. Worst case, start with a new project, in which you are able to use that functionality, and add back in all your files.