Interfaces between VB. NET development and SAP

The sap r/3 system is the most advanced and stable ERP system in the industry. The proportion of large international and domestic enterprises adopting this system is far ahead of that of other ERP systems. Sap r/3 has a built-in secondary development platform called ABAP, which is similar Programming Language . ABAP has relatively weak functions in report output (it can only be printed on the screen by row or exported to excel). Therefore, it is often necessary to develop reports externally in daily work. Program . The program interface is used to automatically read data tables (Views) of sap r/3, process them externally, and generate report styles that meet Chinese habits using tools such as Crystal Reports.

Sap r/3 interfaces include RFC, IDOC, and bapi. This document describes the relatively simple RFC (romote function call, remote function call ). The RFC calling principle of the SAP system is actually very simple. There are some C/S systems similar to the three-layer architecture. Third-party customer programs call the standard or custom functions in SAP through interfaces, obtain the data returned by the function for processing and display or print it. The following is a model called by RFC:
This article does not discuss the development of sap r/3 functions, because SAP companies generally have dedicated ABAP developers. If you have the opportunity to access the ABAP platform, you can use the transactionCodeSe37 enters the "function compiler" of the ABAP development platform for function development and testing.

The following uses VB as an example to describe how to develop the RFC for the SAP interface. When installing the sap gui client on the SAP client, be sure to install the included SDK package (the most secure option is full installation ). RFC interface program development mainly uses the "sap. Functions" control to simulate user logon and function calling of the sap gui client in an external program, and then return the function value. See the following program snippets and key annotations (especially test_click ()):

Private sub commandementclick () 'Define the R/3 user name and password variable (the user name should be permitted by the sap administrator to run the function) Dim LOGNAME as string * 22, password as string * 22 Call logonr3 (LOGNAME, password) 'to call the sap logon interface program If logflag then' calls the production and development system switch Statusbar1.visible = true Statusbar1.simpletext = "logging on to sap r/3 ..." Dim r3appserver as string, r3client as string, r3systemno as string If form2.opprd. value then 'Modify the following server parameters according to the customer's configuration. R3appserver = "10.3.1.4" 'production system server IP Address R3client = "800" 'production system group code R3systemno = "00" 'production System No. Else R3appserver = "10.3.3.1" 'Development System server IP Address R3client = "101" R3systemno = "00" End if Unload form2' releases form2, and all controls and values are unavailable Set functions = Createobject ("sap. Functions") 'creates the local object of the RFC. Set connect = functions. Connection 'sets the connection Connect. applicationserver = r3appserver 'value Server IP Address Connect. Client = r3client 'value SAP group code Connect. Language = "ZH" 'sets the SAP system interface to Chinese Connect. User = trim (LOGNAME) 'value for SAP login Username Connect. Password = trim (password) 'value for the SAP logon User Password Connect. systemnumber = r3systemno 'value for the SAP system number If not connect. Logon (0, true) then' software logs on to sap and determines Msgbox "failed to log on to sap r/3. Please log on again! ", Vbokonly + vbexclamation," system prompt" Command1.setfocus Else' sap login successful Command1.enabled = false Command2.enabled = true Test. Enabled = true End if Statusbar1.simpletext = "" Statusbar1.visible = false End if End sub Private sub command2_click () 'log out of SAP Connect. Logoff Command2.enabled = false Command1.enabled = true Test. Enabled = false End sub Private sub command3_click () 'exit the sap interface demo program If form1.command2. enabled then Msgbox "Disconnect the sap r/3 system before exiting! ", Vbokonly + vbinformation," system prompt" Else End End if End sub Private sub form_load () Command2.enabled = false Test. Enabled = false Logoflag = false End sub Private sub test_click () 'sap RFC Remote Call processing master demo Dim getcustomers as object Dim MERs as object Dim I as integer 'Remotely run the sap internal function rfc_customer_get through the RFC Interface 'Assign the sap built-in function name to be called Set getcustomers = functions. Add ("rfc_customer_get ") Getcustomers. Exports ("kunnr") = "0000000103" 'value to the function entry (Customer Code) 'Assign the query table name to the function entry Set MERs = getcustomers. Tables ("customer_t ") If getcustomers. Call then' is successfully invoked, all information entries of the customer are displayed. For I = 1 to mers MERs. rowcount Msgbox MERs (I, "kunnr ") Next I Else Msgbox "Search error! Error message: "+ getcustomers. Exception End if End sub

RFC call of SAP is the simplest and easiest method in its interface technology. This method is easy to develop and is especially suitable for external report development. However, it is less efficient to query large data volumes. After you have mastered it, You can further learn advanced IDOC and bapi interface development technologies.