To be able to quickly recognize if an appointment from the ERP-software was already synchronised to Outlook, E-Sync had to be able to recognize the appointments already in Outlook. Since all fields I filled until now are standard-fields that anyone can fill or change in Outlook, I needed custom-fields. For C#, this is not a very well documented area, like more Office development stuff. Lot’s of code reference and samples in VBA or VB, if you’re lucky VB.NET, but C# is scarce. I’m not sure why this is, C# has been around long enough now.
Anyways, E-Sync now recognizes the appointments it made in Outlook by the same unique number that is used in the ERP-software. And since there is no default-form in Outlook showing custom-fields, the user can’t see or change it.
I’ll have to talk to the manufacturer of the ERP-software first, but I guess this is the basis for 2-way synchronisation. And since the user can’t see/change the custom-field, the appointment has to be created in the ERP-software.