Cast error when drawing Subgraphs in MSAGL

Question

I have a root Subgraph object with four child Subgraphs each containing a few Nodes. I have added all the Subgraphs and Nodes to the Graph and set the RootSubgraph on the Graph. However, when trying to draw the Graph I get a cast error from within the library (Microsoft.Msagl.GraphViewerGdi.Draw.cs, line 1044) where the GeometryNode of a Subgraph is cast to a Cluster. The GeometryNode is set to a Cluster in GeometryGraphCreator.ProcessSubgraphs and the error message gives me no information about why the cast fails. How can I fix this?

For now I've simply set the Label to null to avoid the drawing code but I would like to use a label eventually.

Answer 1

The problem was in my initialisation of the Subgraph:

var subgraph = new Subgraph(id)
{
    Attr =
    {
        Id = id,
        FillColor = fillColor,
    },
    Label =
    {
       FontSize = 10,
       Text = id
    }
};

Assigning the Label property this way skipped some extra set up code needed to correctly link the Label with the Subgraph. Leaving it out altogether lets the constructor handle the Label itself.