Frequently Asked Questions

Got a question? We've got answers. If you have some other questions, just contact us.

What Runtime / Frameworks are supported

We support .NET Framework (min 4.5), and .NET Core (min 3). You can use any third party framework like PRISM, MVVMLight,... or controls from a third party vendor like DevExpress, Telerik,...

I have multiple Application resources? What should i do?

FastWPF supports multiple application resources. Within the preview window you can choose which application resources should be loaded for the designer, you can also decide to not load any resources if you want to.


Since the beginning of the XAML development there has been the designer property "DesignerProperties.IsInDesignMode". The designer respects this setting but does not need it, because we show you a "real" preview of your application it is not always wanted. For that reason you can disable this setting if you want to.

Visual Studio is slow, does the designer make it even slower?

No, because the whole designer is a dedicated process, and it is running outside of Visual Studio, event the UI of the designer is out of process. If the code, or the XAML leads to some crash, just the designer process is exiting, Visual Studio stays vital.

Is the designer 64 Bits or 32 Bits?

Dependes on your needs, you can switch between 32-Bits and 64-Bits, whithout restarting Visual Studio.

Anything special about ResourceDictionaries / Generic.xaml

The designer supports it that you can open even a file which consists of just a resource dictionary. You will get an overview over all keys which you have defined implicitly or explicitly, and you will see the value.

How can i design the DataContext

You can design the DataContext in three different ways, you can edit the values directly within the designer, you can take a snapshot of a running application or a method can be called.

It is very importan that you assign your design DataContext at the root of the document.