Binding scrollgrids to arrays in dialogs

Program arrays act as data model that are bound to form scrollgrids, when implementing list dialogs.

Identifying list views in program dialogs

In list dialogs such as the INPUT ARRAY or DISPLAY ARRAY, the screen array identifies the record list element in the current form to be bound to the program array used by the dialog.

In this example, the INPUT ARRAY uses the custlist screen array of the form, and binds the custarr program ARRAY with the code:

INPUT ARRAY custarr FROM custlist.*

The screen array members are associated with the program array record members by position. The order and number of the screen array elements is important as they are bound by position to the members of the program array.

The position of the SCROLLGRID fields, however, can differ from the members of the screen array and program array.

To omit fields in the SCROLLGRID layout, yet include them in the definition of the screen array, and define the fields as PHANTOM fields in the form definition file. The program array can then be defined from the database table definition with the DEFINE LIKE instruction:

DEFINE custarr DYNAMIC ARRAY OF RECORD LIKE customer.*

The array is usually defined with a flat list of members with

ARRAY OF RECORD / END
RECORD

. However, the array can be structured with sub-records and still be used with a list dialog. This is especially useful when you need to define arrays from database tables, and additional information needs to be managed at runtime (for example to hold image resource for each row, to be displayed with the IMAGECOLUMN attribute):

SCHEMA shop
DEFINE a_items DYNAMIC ARRAY OF RECORD
                   item_data RECORD LIKE items.*,
                   it_image STRING,
                   it_count INTEGER
               END RECORD
...
DISPLAY ARRAY a_items TO sr.*
   ...

Defining screen arrays

The SCROLLGRID container is bound to a screen array defined in the INSTRUCTIONS section, by the name of the form fields used in the screen array definition.

The form data type and additional properties are defined in the ATTRIBUTES section as form fields:

LAYOUT
SCROLLGRID (WANTFIXEDPAGESIZE = NO)
{
 Id:   [f1    ]
 Name: [f2           ][f3           ]
}
END
END
...
ATTRIBUTES
EDIT f1 = customer.cust_num;
EDIT f2 = customer.cust_fname, 
EDIT f3 = customer.cust_lname;
...

Each form field of the scrollgrid must be grouped in the INSTRUCTIONS section in a SCREEN RECORD definition.

INSTRUCTIONS
SCREEN RECORD custlist( cust_num, cust_fname, cust_lname );
END