What
you can do with DataWindow object properties
The DataWindow object defines the way data is displayed in a
DataWindow control. It contains controls that represent the columns,
text labels, computed fields, and images.
The properties of the DataWindow object and its controls store the
information that specifies the behavior of the DataWindow object. They
are not properties of the DataWindow control, but of the DataWindow
object displayed in the control.
Terminology
When you are programming for DataWindows, there are several
types of expressions involved.
A DataWindow expression is an expression assigned as a value to
a DataWindow property and is evaluated by the DataWindow engine. The
expression can refer to column data and can have a different value for
each row in the DataWindow.
A DataWindow property expression is an expression in your code
that gets or sets the value of a DataWindow property. Its effects are
equivalent to what the Describe and Modify methods do.
A DataWindow data expression is an expression in your code that
gets or sets data in the DataWindow. Its effects are similar to what
the SetItem and several GetItem methods do.
Types of values
Property values can be constants or can be DataWindow expressions.
DataWindow expressions allow the property value to be based on other
conditions in the DataWindow, including data values. Conditional
expressions based on data can give the property a different value for
each row.
Getting and setting values
You establish initial values for properties in the DataWindow
painter. You can also get and set property values at runtime in
code.
There are several techniques for accessing property values. A
particular property might be accessible by a subset of those techniques.
For example, some properties are read-only at runtime, some can be set
only at execution, and some accept only constants (not DataWindow
expressions) as values.
For a complete list of properties and the ways you can access each
one, see DataWindow Object
Properties
Examples: ways of setting the Border
property
This table lists the ways you can access a property, using the
Border property as an example:
|
What you can do with properties |
How to do it, using the Border property as an |
What happens |
|---|---|---|
|
Set the initial value of the property in the |
Property sheet, General tab, Border |
The Border property takes on the value you set |
|
Specify the value of the property at runtime based |
Property sheet, General tab, Border box, Expression |
In Preview and at runtime, the border changes as For example, an expression can give To see the effect in the Preview |
|
Get the value of the property at runtime in |
Property expression for the Border property or |
Both the expression and the Describe method return |
|
Change the value of the property at runtime in |
Property expression for the Border property or |
At runtime, the value of the property changes when |
|
Set the initial value of the property at runtime in |
SyntaxFromSQL method |
When SyntaxFromSQL executes, the border value of PowerBuilder SyntaxFromSQL is a |