Expandable hierarchy

I’ve just begun to look at the samples and am trying to create my own web app that does the following:
Reads in a hierarchical data structure and displays it using GoDiagram and allow every node to expand and collapse. Kind of like a windows explorer tree view of files and directories. Is GoDiagram the best tool to use for this? If so, I would think this would be a very common task, but I’m having a trouble getting info from the samples on how to do this. Specifically subgraphs. It seems like every sample handles subgraphs differently. I’m not sure what my question is :), I’m just trying to look for some tips on how to accomplish this task outlined above.

SubGraphApp and TreeApp are probably the samples most relevant to what you want to do. Whether you want to use GoSubGraphs or just use simpler nodes (as a TreeView imitates in a limited fashion) depends on the syntax and semantics that you need.

Appearantly in the TreeApp a child node can’t have two parents? For example if you create 3 nodes (0, 1, 2), and then drag link from 0 to 1 and then try to drag a link from 2 to 1 it won’t work. So, can one node only have one parent node?

It wouldn’t be a tree then, would it? Unless you considered the opposite direction for links.
That behavior is controlled by the GoDocument.ValidCycle property.