In SAP ABAP, how can you provide programmatic value help for a field without using a predefined search help or matchcode object?

Introduction / Context:
In SAP ABAP, users often press the F4 key to request value help for an input field. While standard search helps and matchcodes provide this functionality in many cases, there are situations where developers must build value help programmatically. This question tests your knowledge of how to provide custom F4 help without creating a Data Dictionary search help object, by using ABAP events and function modules.

Given Data / Assumptions:

• We have an input field in a selection screen or a custom screen.
• We do not want to use a predefined search help or matchcode object from the Data Dictionary.
• We need to provide custom value help when the user presses F4.

Concept / Approach:
SAP ABAP allows developers to intercept the F4 help request through events such as AT SELECTION-SCREEN ON VALUE-REQUEST or through module pool screen processing. Within this event, the developer can call the function module F4IF_INT_TABLE_VALUE_REQUEST, which displays an F4 help dialog based on an internal table of possible values. This approach is called programmatic value help because the developer controls which values are shown and how they are built, without relying on a predefined search help object.

Step-by-Step Solution:
Step 1: In a report, define the selection screen parameter for which you want to provide F4 help. Step 2: Implement the event AT SELECTION-SCREEN ON VALUE-REQUEST FOR parameter_name. Step 3: Inside this event, build an internal table containing the possible values and their descriptions. Step 4: Call function module F4IF_INT_TABLE_VALUE_REQUEST, passing the internal table and field information to display the custom F4 popup. Step 5: The user selects a value from the popup, and the chosen value is automatically returned to the input field.

Verification / Alternative check:
You can verify this approach by writing a small demo report, defining a parameter, and coding the AT SELECTION-SCREEN ON VALUE-REQUEST event. After calling F4IF_INT_TABLE_VALUE_REQUEST, run the program and press F4 on the field. If the custom list of values appears and the selected value is returned, your programmatic value help is working correctly. This confirms that programmatic F4 help does not require a Data Dictionary search help.

Why Other Options Are Wrong:
Option A is incorrect because defining a foreign key relationship alone does not automatically give full custom F4 help without a search help object. Option B is incorrect because writing a BAPI by itself does not connect directly to the F4 mechanism; you still need to call it from ABAP code in the value help event. Option D is incorrect because enabling debug mode in SE80 does not provide automatic value help; debug mode is for troubleshooting, not for user assistance.

Common Pitfalls:
A common mistake is to forget to implement the correct event (such as AT SELECTION-SCREEN ON VALUE-REQUEST) for selection screens, which means the F4 key uses default behaviour. Another pitfall is not filling the internal table correctly, leading to an empty or confusing F4 popup. Developers also sometimes misuse F4IF_INT_TABLE_VALUE_REQUEST parameters, causing the selected value not to return to the field. Carefully testing the F4 help and checking parameter mappings is important for reliable programmatic value help.

Final Answer:
You can provide programmatic value help without a predefined search help by using the event AT SELECTION-SCREEN ON VALUE-REQUEST or equivalent and calling function module F4IF_INT_TABLE_VALUE_REQUEST to display custom F4 help values.