Disabling specific rows or cells in an ALV Grid (SAP List Viewer) offers enhanced user experience by preventing unintended changes to crucial data. This functionality is particularly useful when displaying information that should only be viewed, not edited, based on certain conditions. While the standard ALV Grid doesn’t directly support row-level disabling, this article will demonstrate how to achieve this using the REUSE_ALV_GRID_DISPLAY_LVC function module and the HANDLE_STYLE field.
Understanding the Disabling Mechanism
The key to disabling specific rows lies in manipulating the cell styles. By leveraging the HANDLE_STYLE field in conjunction with the STYLEFNAME parameter of the layout structure, we can apply specific styles, including the disabled state, to individual cells. This approach allows for granular control over the editability of each row within the ALV Grid. The code example below utilizes the CL_GUI_ALV_GRID=>MC_STYLE_DISABLED constant to achieve this.
Code Implementation for Disabling Rows
The provided ABAP code snippet demonstrates how to disable a specific row (the 6th row in this example) in an ALV Grid. Let’s break down the crucial parts:
DATA: LS_EDIT TYPE LVC_S_STYL,
LT_EDIT TYPE LVC_T_STYL.
DATA: BEGIN OF IT_VBAP OCCURS 0,
VBELN LIKE VBAP-VBELN,
POSNR LIKE VBAP-POSNR,
HANDLE_STYLE TYPE LVC_T_STYL, "FOR DISABLE
CHECK(1),
END OF IT_VBAP.
...
SY-TABIX = 6. " Specify the row to be disabled
LS_EDIT-FIELDNAME = 'CHECK'. "Disable the checkbox in this example
LS_EDIT-STYLE = CL_GUI_ALV_GRID=>MC_STYLE_DISABLED.
...
INSERT LS_EDIT INTO TABLE LT_EDIT.
INSERT LINES OF LT_EDIT INTO TABLE LS_OUTTAB-HANDLE_STYLE.
MODIFY IT_VBAP INDEX SY-TABIX FROM LS_OUTTAB TRANSPORTING HANDLE_STYLE.
X_LAYOUT-STYLEFNAME = 'HANDLE_STYLE'. " Link layout with style
CALL FUNCTION 'REUSE_ALV_GRID_DISPLAY_LVC'
EXPORTING
...
IS_LAYOUT_LVC = X_LAYOUT
...
TABLES
...This code first defines a style structure (LS_EDIT) and populates it with the necessary information to disable the ‘CHECK’ field (a checkbox in this case). Then, it inserts this style into the HANDLE_STYLE table of the specific row in the output table (IT_VBAP). Finally, it links this style to the layout using X_LAYOUT-STYLEFNAME.
Applying Conditional Disabling
The example disables the 6th row using SY-TABIX = 6. However, this can be easily adapted to disable rows based on specific conditions. By incorporating a LOOP statement and conditional logic (e.g., IF), you can dynamically disable rows based on the contents of your data.
LOOP AT IT_VBAP INTO LS_OUTTAB.
IF LS_OUTTAB-VBELN = 'YOUR_CONDITION'.
... " Code to disable the checkbox for this row
ENDIF.
ENDLOOP.This allows for flexible and powerful control over the user interface, ensuring that only relevant fields are editable.
Conclusion: Precision Disabling in ALV Grid
Disabling specific rows or cells in an ALV Grid, while not a standard feature, can be effectively implemented using the techniques described above. By leveraging the HANDLE_STYLE field and incorporating conditional logic, developers can create user-friendly interfaces that prevent unintended data modification and enhance overall user experience. This method provides a robust solution for controlling data entry and display within SAP applications.
