TimelineView.StartField Property (Outlook)
Returns or sets a String value that represents the name of the property that starts the time duration for Outlook items displayed in the TimelineView object. Read/write.
The values of the StartField and EndField properties indicate which Outlook item properties are used by the TimelineView object to represent the duration of an Outlook item. Both custom and built-in properties can be specified, but only date/time properties are allowed.