How to access the view model instance in a XAML page's code behind (Xamarin Forms) in Prism

Question

Below is the definition of my page in Xamarin Forms with Prism MVVM framework:

<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:prism="clr-namespace:Prism.Mvvm;assembly=Prism.Forms"
             prism:ViewModelLocator.AutowireViewModel="True"
             xmlns:maps="clr-namespace:Xamarin.Forms.Maps;assembly=Xamarin.Forms.Maps"
             x:Class="MyProject.UI.Modules.Views.MapPage">

.....
</ContentPage>

Unfortunately Xamarin maps are not MVVM-ready when it comes to binding pins, etc. Therefore, I need to make some code changes in the C# code behind of the page. How can I access the instance of the ViewModel interacting with this page in the code behind?

Answer 1

You could always monitor for property changes on the ViewModel and use the values to update the map. To get a hold of the ViewModel, just cast your BindingContext

Example : ((MainPageViewModel)this.BindingContext)

Example link : https://github.com/PrismLibrary/Prism-Samples-Forms/blob/7b0ce9ca31f07dea5020dbd5875d16f18bcdf09a/ContosoCookbook/ContosoCookbook/ContosoCookbook/Views/MainPage.xaml.cs#L16