[SOLVED] WPF XAML designer showing bound property names instead of property values

WPF XAML designer showing bound property names instead of property values

One of my XAML files shows a strange behaviour in the XAML designer (but not during runtime):

public class MyDesignTimeViewModel
{

    public MyDesignTimeViewModel()
    {
        MyText = "abc";
        MyInt = 5;
    }

    public string MyText { get { ... } }
    public int MyInt { get { ... } }
}

Then in XAML:

<UserControl xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
             ...
             d:DataContext="{d:DesignInstance vm:MyDesignTimeViewModel}"
             >
    <TextBlock Text="{Binding MyText}" />
    <TextBlock Text="{Binding MyInt}" />
</UserControl>

In the XAML designer, the two TextBlock instances show the following content:

MyText
0

The XAML designer shows the property name of the string property, and for the int property, it shows a 0.

There's no error in the error window. Furthermore, it seems to actually read the properties, because if I change the binding to a non-existing property name, the content disappears.

I've restarted Visual Studio and my PC and deleted the .suo file.

Any explanation for this behaviour?

Solution

Turns out the missing thing was the IsDesignTimeCreatable attribute:

d:DataContext="{d:DesignInstance vm:MyDesignTimeViewModel, IsDesignTimeCreatable=true}"

With that attribute, everything works as expected.