CICS Menu-Driven Application

A menu-driven application starts every user session at a menu screen. The menu program shows the options, reads the choice, and transfers control to the right transaction.

This is the same INVMENU-style design used in the CICS program design material: one menu program routing to many application programs.

What the menu program does

• The menu program is the entry point of the application, with a trans-id like BKMN or INVMENU.
• It displays numbered options (1 = Inquiry, 2 = Update, 3 = New account) plus instructions for PF keys.
• The user types a choice and presses Enter; the program validates it and XCTLs to the selected program.
• The menu program never updates files itself - it only routes control.
• Navigation stays consistent everywhere: PF3 always means back to the menu, PF12 cancels the current screen.

Handling the user choice with AID keys

• EIBAID tells which key was pressed: DFHENTER, DFHPF3, DFHPF12 and so on.
• Use EVALUATE on EIBAID: Enter processes the typed option, PF3 exits, other keys show an error.
• Read the option field from the symbolic map and check it is within the valid range.
• An invalid choice redisplays the menu with an error message - it must never abend.
• Pass shared context such as user id or branch code in the COMMAREA so every program knows who is signed on.
• Example:-
  
  EVALUATE EIBAID WHEN DFHENTER PERFORM 2000-PROCESS-OPTION WHEN DFHPF3 EXEC CICS XCTL PROGRAM('SIGNOFF') END-EXEC WHEN DFHPF12 MOVE 'REQUEST CANCELLED' TO MSGO WHEN OTHER MOVE 'INVALID KEY PRESSED' TO MSGO END-EVALUATE.

Navigation rules used in real projects

• Every application screen supports PF3 back to the menu - code it in each program, not just the menu.
• PF12 cancels the current operation: on a key map it returns to the menu, on a data map it redisplays the key map.
• Keep the menu map simple: few fields, clear numbering, and the cursor positioned in the option field.
• Log the selected option and user id to a TD queue for a simple audit trail.
• The diagram below shows how the menu program routes control between the banking transactions.