Group Items Example in .NET COBOL Interoperation

In the InterfacingWithStdCOBOL.sln solution, the second pair of projects, StdCbl02*, shows a COBOL program using group items. This is more representative of real COBOL than the StdCbl01 program. C# doesn't have the concept of group items, so we write a proxy class to manipulate the data and act as an interface between the COBOL and the C#.

The StdCbl02 projects contain the following programs:

• StdCbl02.cbl. This program is procedural COBOL. It is compiled to managed code without any changes.
• StdCbl02.cpy. This copybook defines group items, which contain the parameters passed to and from StdCbl02.cbl, as follows:

  Lines 06-09:

  01 INPUT-FIELDS.
     03 IN-FIELD01     PIC  X(01).
     03 IN-FIELD02     PIC  9(03). 
     03 IN-FIELD03     PIC S9(05)V99    COMP-3.
  

• ooiStdCbl02.cbl. This program acts as an interface (a proxy) between the C# and the unchanged COBOL StdCbl02.cbl. It manipulates the group items as follows:
  • Defines object properties to contain the data passed to and from the client C# program, as follows:

    Lines 33-35

    01 InField01  Object Reference StringClass  property AS "InField01".
    01 InField02  Binary-Short                  property AS "InField02". 
    01 InField03  Object reference DecimalClass property AS "InField03". 
    

  • Takes the input data from the object properties set in the C# client program and puts this data into the COBOL fields defined in the copybook, as follows:

    Lines 52-54:

    Set IN-FIELD01              to InField01
    Set IN-FIELD02              to InField02
    Set IN-FIELD03              to InField03
    

• StdCbl02Client.cs. This is the client program, written in C#. It does the following:
  • Sets the object properties of the class OOiStdCbl02

    Lines 25-27

    objStdCbl02.InField01  = "A";			    
    objStdCbl02.InField02  = 999;  
    objStdCbl02.InField03  = 12345.67M; 
    

  • Invokes the method ExecStdCbl02 in the newly written proxy class, as follows:

    Line 31:

    objStdCbl02.ExecStdCbl02();