Selection boxes in an INPUT statement are available on
mainframe computers only. For other platforms, selection boxes may be defined
in the map editor only.
Selection boxes can be attached to input fields. They are a comfortable alternative to help routines attached to fields, since you can code a selection box direct in your program. You do not need an extra program as with help routines.
You may define a selection box clause for every INPUT
variable of type alpha, regardless if this field is an input or output field,
or both.
The syntax is:
| SB=operand1 [,operand1]... |
where operand1 represents a value
operand which is used to fill up the selection box with items.
| Operand | Possible Structure | Possible Formats | Referencing Permitted | Dynamic Definition | |||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| operand1 | C | S | A | A | yes | no | |||||||||||||||
With SB, you specify the values to be displayed within the selection box.
To assign a selection box to a field, specify the attribute
SB for an alpha INPUT field in your Natural program
using the following example syntax:
INPUT #FLD (SB='value1', #ITEM1, #ITEM2(1:3), #ITEM3(*))
The following topics are covered below:
It is possible to assign both a selection box and a help routine to a field.
Selection boxes can be defined for every variable field in an
INPUT statement.
Exceptions are the following:
| System Variables | For example: *PROGRAM,
*COM |
| Named Constants (mainframe only) | defined with a CONST clause of
DEFINE DATA
statement.
|
In addition to the SB attribute, other attributes
can be defined as well, for example: AD or
CD.
The selection box field does not have to be modifiable, as is the case
with AD=A
or AD=M.
In other words, it is possible to provide a selection box (and select values)
even for a write-protected output field, such as
AD=O.
If you use AD=O, the user is forced to choose from a set of
predefined values, which themselves appear in a selection box.
When a program containing a selection box is executed, the selection box is positioned on the screen according to the same positioning algorithm used for help windows; that is, the size and position of the selection box are determined automatically, "near" the field.
The color and intensified attributes assigned to the field are also applied to the values displayed in the corresponding selection box.
If an edit mask has been defined for the field, the edit mask is applied to all selection box values.
Using the INPUT
statement, you can define an edit mask for a field. This is demonstrated in
following code example.
DEFINE DATA LOCAL 1 A(A4) END-DEFINE MOVE 'ABCD' TO A * SET KEY PF1 = HELP FORMAT KD=ON * INPUT A (AD=M EM=X.X.X.X SB='1234','WXYZ') WRITE A END
The line size of the selection box matches the field length to which the box corresponds.
If a value intended for the selection box exceeds the line size of the selection box, the value is truncated.
Selection box values are displayed in the order they appear in the
SB attribute.
For a field with attached selection box, an indicator "V" is displayed next to the field.
To open a selection box, there are two ways to open a selection box:
Enter a question mark (?) in the V-field and press ENTER.
Or position the cursor on the V-field and press the help key (for example, PF1), if you have defined it to do so. See the next section for more details.
To define a help key to invoke the selection box, you can define a help-key (for example, PF1) to make invoking the selection box much simpler.
This is done by adding the following line of code to your program:
SET KEY PF1=HELP
There are two ways to scroll in a selection box:
By putting the cursor on the MORE line and pressing
ENTER.
Or by using the terminal
commands %W- and
%W+ assigned to PF-keys (for example,
PF7/PF8).
A value is selected from the selection box and copied into the field by putting the cursor on the value and pressing ENTER.
Lines with the same content which directly follow each other are suppressed.
For example, the following code
INPUT #FLD (SB='123', '456', 'XYZ', 'XYZ', 'XYZ', 'ABC', 'DEF')
produces the following output to the selection box:
123 456 XYZ ABC DEF
In the preceding example, XYZ is only displayed once. The
other occurrences are considered redundant since they directly follow one
another.
However, this line of code
INPUT #FLD (SB='123', 'XYZ', '456', 'XYZ', 'ABC', 'XYZ', 'DEF')
produces the following output to the selection box:
123 XYZ 456 XYZ ABC XYZ DEF
In this case, all three occurrences of XYZ are displayed,
since they do not directly follow one another.
A blank line is only displayed the first time it appears; all subsequent blank lines are suppressed.
The number of operands in the SB clause is limited to
20.
The maximum number of values in a selection box is 248. When that limit has been reached, further values are not displayed. No error message is issued when the limit has been exceeded.
