Note:   The curly braces enclosing {ALL} are part of format 6 above.

Where:

Because a drop box list is in drop down form, a drop box takes a smaller amount of space on the screen than a comparable list box. In addition, ProvideX automatically supplies vertical scrollbars if the number of elements overflows the dropdown box size. Combine these features to optimize the screen design when display space is at a premium.

Drop Box Properties

The Apostrophe Operator can be used with the unique logical identifier (ctl_id) to dynamically read and alter a wide variety of control attributes (properties) directly from the programming language. The list of properties available for manipulating a drop boxes are described in Control Object Properties, .

DROP_BOX ctl_id,@(col,ln,wth,ht)[,ctrlopt]

Use this format to define or create a drop box and give it a unique identifier in ctl_id. You can use the FNT= option to establish the font for it. If you omit the font option, ProvideX uses the system default font. Use FNT="*" (asterisk) to set the font as standard text mode fixed font.

The following example creates a drop box that generates a CTL=100 when any item is selected from it. It is loaded with the items Cat, Dog, and Pig.

0010 DROP_BOX 100,@(2,14,12,6)
0020 DROP_BOX LOAD 100,"Cat/Dog/Pig/"

DROP_BOX REMOVE ctl_id[,ERR=stmtref]

Use the DROP_BOX REMOVE format to delete a drop box.

DROP_BOX {DISABLE | ENABLE}ctl_id[,ERR=stmtref]

Use DROP_BOX DISABLE to gray out a drop box so that it will be visible but inaccessible, to users. To reactivate it, use DROP_BOX ENABLE.

DROP_BOX GOTO ctl_id[,ERR=stmtref]

Use the DROP_BOX GOTO format to set the focus on a drop box, ready for the user's next input.

Use DROP_BOX LOAD to add or delete the elements listed in a drop box. To add elements, you can load them from a delimited string, as an array of string elements, or individually. If you load more items into the list than the drop down box can display at one time (because of its physical size), ProvideX automatically supplies scrollbars.

DROP_BOX LOAD ctl_id,dlm_list$[,ERR=stmtref]

Load List. When you load a drop box from a delimited string, the last character in the string must be the delimiter. That delimiter must be identical to the separator between the elements in the string. For example, in the delimited string below, the delimiter is the slash "/". It ends the string and separates the elements; e.g., DROP_BOX LOAD 12000,"Fox/Cat/Dog/Cow/Sheep/Horse/Pig/Elephant/Ant/"

To clear all elements from a drop box, use a null string; e.g.,

DROP_BOX LOAD 86, ""

DROP_BOX LOAD ctl_id,array_name${ALL}[,ERR=stmtref]

Load Array. Use this format to load a complete array into the drop box. Note that the curly braces enclosing {ALL} are part of the syntax; e.g.,

DROP_BOX LOAD 16000,A${ALL}.

DROP_BOX LOAD ctl_id,index,{lement$ | *}[,ERR=stmtref]

Load Element. When you load individual drop box elements, use an integer value to state the index of the element before which to insert the element being loaded. For instance, if index is 1, the new element will be inserted before 1, at the start of the list. If index is 0 (zero), the new element will be appended to the end of the list.

To delete or remove a specified element from a drop box, use an asterisk in place of the element string; e.g.,

DROP_BOX LOAD 86,4,* ! Deletes list element 4 from a box whose ctl_id is 86.

DROP_BOX FIND ctl_id,index,var$[,ERR=stmtref]

Use the string variable in DROP_BOX FIND to retrieve a specific element from a drop box.

Retrieve complete contents

DROP_BOX FIND ctl_id, 0 ,var$[,ERR=stmtref]

If the index value of zero (0) is used PxPlus will return the complete contents of the drop box.

This is a +PxPlus Exclusive

Use the DROP_BOX READ formats to read which element the user has selected from the drop box. You must read the user's selection before your application can use it. Use the (optional) mode$ variable to have ProvideX return the user's method of selecting an item from the drop box.

Some possible return values are:

• $01$ for MOUSE-CLICK.
• $0D$ for Enter .
• $00$ when the user Tab 's away from the drop box.
• $00$ when the user exits the button control.

After this value is read, the value in mode$ is reset to $00$ (null).

DROP_BOX READ ctl_id,var$[,mode$][,ERR=stmtref]

Read Current Element. With this format, ProvideX returns the string contents of the user's currently selected element in var$ and, optionally, the user's method of selection in mode$.

DROP_BOX READ ctl_id,var[,mode$][,ERR=stmtref]

Read Current Index. Use DROP_BOX READ to read the index of the user's current selection and (optionally) the mode$ of selection.

Use the DROP_BOX WRITE formats described below to update a DROP_BOX to show the current selection.

DROP_BOX WRITE ctl_id,element$[,ERR=stmtref]

Update Current Setting. If you use this format to write an element to a drop box as the current selection, the contents of the string must exactly match the value of one of the elements in the drop box. Otherwise ProvideX returns an Error #11: Record not found or Duplicate key on write.

DROP_BOX WRITE ctl_id,index[,ERR=stmtref]

Update Current Index. You can use the element's index number to write it to the drop box as the current selection.

DROP_BOX WRITE ctl_id,"" [,ERR=stmtref]

Use this format to clear the currently selected entry in drop boxes.

DROP_BOX SET_FOCUS ctl_id,alt_ctl[,ERR=stmtref]

Use the DROP_BOX SET_FOCUS format to define an alternate CTL value to generate whenever focus shifts to a drop box.

DROP_BOX AUTO ctl_id[,ERR=stmtref]

Use the DROP_BOX AUTO format to have ProvideX generate a CTL value to report all changes whenever the user highlights an element from a drop box list.

DROP_BOX {HIDE | SHOW} ctl_id[,ERR=stmtref]

With the DROP_BOX HIDE format, the drop box remains active, but is not displayed. It is still accessible programmatically. Use the DROP_BOX SHOW format to restore the display and user access.