Variable binding in DISPLAY ARRAY
The
DISPLAY ARRAY
statement binds the members of the array of record to the screen array fields specified with the
TO
keyword. Array members and screen array fields are bound by position (not
by name). The number of members in the program array must match the number of fields in the screen
record (that is, in a single row of the screen
array).SCHEMA stock
DEFINE cust_arr DYNAMIC ARRAY OF customer.*
...
DISPLAY ARRAY cust_arr TO sr.*
ATTRIBUTES(UNBUFFERED)
...
END DISPLAY
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
DISPLAY ARRAY
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.*
...
When using the
UNBUFFERED
attribute, the instruction is sensitive to program
variable changes. This means that you do not have to DISPLAY
the
values; setting the program variable used by the dialog automatically displays the data
in the corresponding form
field.ON ACTION change
LET arr[arr_curr()].field1 = newValue()
If the program array has the same structure as a database table (this is the case when the array
is defined with a DEFINE LIKE
clause), you may not want to display/use
some of the columns. You can achieve this by using PHANTOM
fields in
the screen array definition. Phantom fields will only be used to bind program variables,
and will not be transmitted to the front-end for display.