Multiple BindingContext's On Same ContentPage, Two different Views? - xaml

Question

I have a ContentPage with two ContentViews on it and i want to set the binding context for each of them each to their own respective ViewModel (this is my preferred soultion over one massive ViewModel for them combined)
MainPage
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage x:Class="MVVMFramework.VVMs.Main.MainPage"
xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:local="clr-namespace:MVVMFramework"
xmlns:nav="clr-namespace:MVVMFramework.Navigation.NavigationHeader"
xmlns:vm="clr-namespace:MVVMFramework.VVMs.Main">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="20" />
<RowDefinition Height="200" />
</Grid.RowDefinitions>
//ContentView For Header
<ContentView Grid.Row="0"
HorizontalOptions="Start"
VerticalOptions="Start">
Content="{Binding NavHeader}"
<!--<ContentView.BindingContext>
<nav:NavigationHeaderViewModel />
</ContentView.BindingContext>-->
</ContentView>
//ContentView For Body of the app
<ContentView Grid.Row="1"
Content="{Binding DisplayedView}"
HorizontalOptions="Center"
VerticalOptions="Center">
<!--<ContentView.BindingContext>
<vm:MainPageViewModel />
</ContentView.BindingContext>-->
</ContentView>
</Grid>
</ContentPage>
When I uncomment both bindingcontext attributes the App compiles, and starts to run and then crashes when loading the MainPage.
Am i not implementing this correctly ?, is there another way to do it ?

Answer 1

Answer
You can specify the source for each view's binding using its BindingContext property like so:
BindingContext="{Binding Source = {Your Binding Source}}"
Sample App
Here's a sample app that shows how to reference multiple view models from the same ContentPage: https://github.com/brminnick/MultipleViewModelSample/
Code
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage x:Class="MVVMFramework.VVMs.Main.MainPage"
xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:local="clr-namespace:MVVMFramework"
xmlns:nav="clr-namespace:MVVMFramework.Navigation.NavigationHeader"
xmlns:vm="clr-namespace:MVVMFramework.VVMs.Main">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="20" />
<RowDefinition Height="200" />
</Grid.RowDefinitions>
<ContentView
Grid.Row="0"
Content="{Binding NavHeader}"
HorizontalOptions="Start"
VerticalOptions="Start"
BindingContext="{Binding Source = {nav:NavigationHeaderViewModel}}"/>
<ContentView
Grid.Row="1"
Content="{Binding DisplayedView}"
HorizontalOptions="Center"
VerticalOptions="Center"
BindingContext="{Binding Source = {vm:MainPageViewModel}}"/>
</Grid>
</ContentPage>