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Various
properties of Graphical Control Objects
in ProvideX (button, drop box, scrollbar ...) can be
referenced and modified dynamically
using a control’s assigned CTL value (ctl_id)
followed by the apostrophe operator and one of the
associated property names
(listed above). This chapter describes the various
properties and discusses how they are used to define
controls in ProvideX. |
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| *Note* |
In
this reference, some properties are denoted with dollar
signs to indicate that they represent string values;
e.g., 'Msg$ or 'Tip$. |
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For
a complete list of graphical control objects and their
properties, see Graphical Control Objects.
The Properties List, provides a complete
alphabetically- arranged list of valid property names and
their definitions. Special property groupings (e.g.,
state indicators or multi-property access) are described
in the section Compound Properties. |
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| Using
Property Names |
As
mentioned earlier, access to control object properties is
provided via the apostrophe operator. (For complete
syntax and usage refer to the Apostrophe Operator). For example, a button’ location, size,
text, and colour would be represented by properties named
Height, Font$, Text$,
TextColour$, etc. If the variable
MyButton contained the CTL value associated with a
button, you could change its text as follows:
MyButton'Text$ =
"Hit me now"
Other common properties
include:
| Property |
Description |
| 'Col |
Column |
| 'Line |
Line |
| 'Cols |
Width
of the control |
| 'Lines |
Height
of the control |
| 'Tip$ |
Tip
for the control |
| 'Msg$ |
Message
line for the control |
| 'Fmt$ |
Format
mask for control |
| 'TextColour$ |
Text
Colour |
| 'Value$ |
Current
value/state of control. |
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| *Note* |
While
programs can access or update property values, properties
cannot be specified as the target for any file I/O or CALL
parameter lists. |
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Generally,
numeric properties are type insensitive; i.e., a property
such as 'Line returns (or receives) a number. If desired,
you can access the same value using the property 'Line$.
This is also true for string properties, assuming that
they only return numeric values. Some properties return different values
based on the type of reference you make. For example,
most colour properties return a text description of the
RGB colour when accessed as a string, or a 24-bit colour
number when accessed as a numeric.
ProvideX also supports
objects that are external to ProvideX this chapter does
not deal with the properties (and methods) that apply to
them. COM and OOP objects/controls are described under
the Apostrophe Operator.
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