As per my knowledge, SAP doesn’t offer any development library for NCo to deal with Idocs. .Net connector is primary used for development of RFC clients.
One of a common method to submit idocs to the SAP system using NCo is by using function module “IDOC_INBOUND_ASYNCHRONOUS”. This function module includes multiple table parameters containing idoc data.
Function Module: IDOC_INBOUND_ASYNCHRONOUS (IDoc inbound processing via tRFC)
Function Group: EDIN
Program Name: SAPLEDIN
Following are the parameters:
Table IDOC_CONTROL_REC_40 contains the control record, IDOC_DATA_REC_40 contains the idoc data segments.
IDOC_DATA_REC_40 contains a field called SDATA. That field contains an Idoc segment data as a single concatenated string with fixed field lengths.