Cannot create unknown type error

Question

Exception: Cannot create unknown type error "'{http://schemas.telerik.com/2008/xaml/presentation}RadDatePicker'"

    public static object Visualize(string filepath)
    {
        try
        {
            var xdoc = new XDocument(XElement.Parse(new StreamReader(filepath).ReadToEnd()));
            Code = xdoc.ToString();
            XmlReader xmlReader = xdoc.CreateReader();
            return XamlReader.Load(xmlReader); //<-- thrown here
        }
        catch(Exception e)
        {
            System.Windows.MessageBox.Show(e.Message,"Visualize error", System.Windows.MessageBoxButton.OK, System.Windows.MessageBoxImage.Error);
            return null;
        }
    }

Exception occurs during runtime when I call the above method with a xaml file that contains this component. If I call this same file, but the part where components are declared is missing, it works fine.

How do I fix it?

Answer 1

The issue may come from your own XAML code which expects a resource not existing on your XAML. If you have a merged resource on your App.xaml, don't expect that it will be seen by XAML control. I ran into the same issue which I had to explicitly define that merged resource again on my control XAML view.

My issue is below, kind of misleading to the actual cause.

Cannot create unknown type '{http://schemas.telerik.com/2008/xaml/presentation}RadGridView'