Hi Richard,
Thanks for using Syncfusion products.
We have checked with your query for loading complex type property values in DropDown control. Currently DisplayMemberPath and ValueMemberPath is not supported in DataFormDropDownItem (DropDown control) in SfDataForm. We have already logged issue report for the same. We will fix and include this fix in our upcoming Volume 3 SP 1 release which is expected to be available by end of month October ,2018. We appreciate your patience until then.
Regards,
Jayaleshwari N.