Viewing Generated Workflow in Designer

Question

I am building up a workflow using the ActivityBuilder and ActivityXamlServices class. When I try to view the outputted XAML in Workflow Designer, I get the following error: ArgumentNullException (errors in SetFlowElementModelItem). It seems as though the workflow designer is having trouble parsing the XAML. If I hand edit the XAML (comparing it to a manually created workflow), I can get it to display. There are some minor differeces such as:

The generated XAML uses the StartNode Attribute (ie StartNode="{x:Reference __ReferenceID5}") whereas the manually created workflow's XAML uses a StartNode element (ie ...)

Also, the generated XAML does not have any elements.

I find it odd that a workflow created by .NET cannot be loaded by .NET.

Has anyone encountered this issue before?

Answer 1

It turns out it was an issue with the FlowSwitch activity. We were not adding an activity to its list of nodes. Also, we were not setting the class name.