PS: I also tried to avoid using RefreshLayout and instead relaunch the OnAppearing method through an event handler as an attempt to redisplay the form and in this case get the following exception: Non-static method requires a target in the GetValue method of FormItemManager.
SPSubburaj Pandian Veluchamy Syncfusion Team August 12, 2019 10:37 AM UTC
Thank you for contacting Syncfusion support.
Based on the shared information, we have analyzed reported issue “DataForm crashes with custom DataFormItemManager class and RefreshLayout”. SetValue method ofDataFormItemManager class will be called twice in DataForm while validation andcommit value and since you are calling RefreshLayout inside SetValue method, Validation and Commit will trigger so SetValue called repeatedly. To overcome this DataForm RefreshLayout can be called only when needed, in your requirement call RefreshLayout only when DisplayMedicalPicker and DisplayNotes values are changed.