I used tree widget in my mashup but don't know why didn't show contents, below is the steps:
1. I create a service to query data from mssql.
2. Bind NetworkConnection DataShape to the result, so now I have few columns including to, from,connectionType.
3.I add the data to the mashup and bind all data to tree widget and grid.
4. Below is the result
Hope someone can help, maybe I missed some steps.
You must set RootParentID to your root node, or at least return the root node as "from"=blank space.