PageFunction is not supported in a Windows Presentation Foundation project - wpf

Question

I'm aware this is the same issue as raised in "PageFunction is not supported in a Windows Presentation Foundation (WPF) project" 2012 - however, I'm unsure as to how to apply the workaround mentioned there, and thought it may be more appropriate to raise this as a separate question. Apologies in advance if this is against the site ethos.
To summarise the problem: I have a C# Visual Studio 2010 WPF project that's a couple of years old, which I'm now trying to open in Visual Studio 2012. Although the project still builds and runs fine, I need to edit the XAML markup, and the Design view in VS2012 complains of "Invalid Markup". The exact error it's tripping up on is:
Page Function is not supported in a Windows Presentation Foundation
(WPF) project
The start of the XAML looks like:
<PageFunction
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:MyNamespace"
x:Class="MyProject.WizardPage1"
x:TypeArguments="local:WizardResult"
KeepAlive="True"
WindowTitle="My Project" Height="350" ShowsNavigationUI="False" Width="700" >
As mentioned in the original question, there are reports of this exact issue on this Microsoft page. There is a workaround mentioned involving "ViewBase", but I cannot see how this relates to the PageFunction problem (I'm very new to XAML so I may be missing something simple).
I've tried opening the project in Blend for VS2012 (the new Preview version that supports non-Windows 8 projects), but that gives the same error about PageFunction not being supported. The recent Update 1 for VS2012 hasn't fixed the problem either.
Can anyone advise what I need to change in my XAML or code-behind in order to be able to visually edit this page?
Or should I give up and just re-download VS2010 in order to edit this project?

Answer 1

Based on the workaround, you'll need to create a class which derives from PageFunction<WizardResult>, and then update your XAML to inherit from that class.
Class:
public class WizardResultPageFunction : PageFunction<WizardResult>
{
}
Code-behind:
Either change the class to inherit from your new class, or remove the base-class declaration completely and let the XAML define the base class:
public partial class WizardPage1
// or:
// public partial class WizardPage1 : WizardResultPageFunction
{
...
}
XAML:
Replace the PageFunction with local:WizardResultPageFunction and remove the x:TypeArguments attribute:
<local:WizardResultPageFunction
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:MyNamespace"
x:Class="MyProject.WizardPage1"
KeepAlive="True"
WindowTitle="My Project" Height="350" ShowsNavigationUI="False" Width="700"
>