Error template not showing for controls within a page

Question

I have a textbox within a page that binds to a model property that is validated, and when there is an error the error template is not shown!

A few points:

1. I have no validation issues for controls in there own window (not within a page displayed in a frame within a window).
2. The error template works, it is displayed for controls within a window.
3. The model is validating because the "Save" button within the page is disabled when a validation error is identified.

I "think" the problem lies with the fact that the control is within a page that is hosted within frame and thus the data context is not being passed to the page as it is seemingly isolated. Could that be the case? and if so how do I go about fixing this issue? and if not what else could it be?

The code (I have of course simplified the code to isolate the issue):

<Page x:Class="PIRS_Client.View.Staff.StaffDetailsView"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:ignore="http://www.ignore.com"
    mc:Ignorable="d ignore"
    DataContext="{Binding StaffDetailsVM, Source={StaticResource Locator}}"
    Height="576" Width="1163">

<Grid>        
    <TextBox HorizontalAlignment="Left" Text="{Binding Model.title, ValidatesOnDataErrors=True}" Height="17" Margin="284,453,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="90"/>
    <Button Content="Save Changes" Command="{Binding SaveDetailsCommand}" IsEnabled="{Binding Model.IsValid}" HorizontalAlignment="Left" Margin="1007,518,0,0" VerticalAlignment="Top" Width="104" Height="23"/>
</Grid>

If I can add any further information or code please just let me know!

Answer 1

Problem solved - it transpires that Windows have a built in adorner layer but Pages do not, I would love to give you a detailed explanation as to why not but I don't know why (read below). But the solution is that you need to wrap your page contents in an adorner decorator to provide them with an adorner layer.

Just to be clear here is the "fixed" code:

<Page x:Class="PIRS_Client.View.Staff.StaffDetailsView"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:ignore="http://www.ignore.com"
    mc:Ignorable="d ignore"
    DataContext="{Binding StaffDetailsVM, Source={StaticResource Locator}}"
    Height="576" Width="1163">

<AdornerDecorator>
    <Grid>        
        <TextBox HorizontalAlignment="Left" Text="{Binding Model.title, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" Height="17" Margin="284,453,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="90"/>
        <Button Content="Save Changes" Command="{Binding SaveDetailsCommand}" IsEnabled="{Binding Model.IsValid}" HorizontalAlignment="Left" Margin="1007,518,0,0" VerticalAlignment="Top" Width="104" Height="23"/>
    </Grid>
</AdornerDecorator>

If you know why pages don't implement the adorner layer and can provide a more insightful answer please feel free to add an explanation as another answer which contains the solution i.e. this and the explanation and I will change your answer to be the correct answer (instead of mine) - just to promote sharing knowledge ;)