CAN-QUERY function

Returns a logical value indicating whether you can query a specified attribute or method for a specified widget.

Syntax

CAN-QUERY ( handle , attribute-name )

handle

An expression that evaluates to a handle. The handle must refer to a valid widget.

attribute-name

An expression that evaluates to a character-string value. The contents of the string must be an attribute or method name. For more information on attributes, see the Handle Attributes and Methods Reference.

Example

The following example prompts for a widget type and an attribute. It creates a widget of the specified type and passes a handle to that widget and the attribute you specified to the CAN-QUERY and CAN-SET functions. Then it reports whether the attribute can be queried or set for that widget.

r-prog.p

DEFINE VARIABLE attribute   AS CHARACTER NO-UNDO FORMAT "x(24)" 
  LABEL "Attribute".
DEFINE VARIABLE queryable   AS LOGICAL   NO-UNDO VIEW-AS TOGGLE-BOX 
  LABEL "Query".
DEFINE VARIABLE setable     AS LOGICAL   NO-UNDO VIEW-AS TOGGLE-BOX 
  LABEL "Set".
DEFINE VARIABLE temp-handle AS HANDLE    NO-UNDO.
DEFINE VARIABLE widget-type AS CHARACTER NO-UNDO FORMAT "x(24)" 
  LABEL "Widget".

FORM widget-type attribute setable queryable.

REPEAT:
  UPDATE widget-type attribute.
  CREATE VALUE(widget-type) temp-handle.
  queryable = CAN-QUERY(temp-handle, attribute).
  setable   = CAN-SET(temp-handle, attribute).
  DISPLAY queryable setable.
  DELETE WIDGET temp-handle.
END.

Notes

For SpeedScript, use with buffer-field, buffer-object, buffer, and query-object handles.

See also

CAN-SET function, LIST-QUERY-ATTRS function, LIST-SET-ATTRS function