Using the DWObject variable in
PowerBuilder
Contents
A PowerBuilder DWObject object is an object that exists within a
DataWindow object. Each column, computed field, text control, or drawing
control is a DWObject.
A DWObject reference allows you to refer directly to controls
within a DataWindow.
You can use a DWObject variable to simplify DataWindow property
and data expressions. A DWObject variable takes the place of several
elements of the control’s dot notation.
The following syntaxes and examples show how using a DWObject
variable affects property and data expressions.
Property expressions
The simple syntax for a property expression is:
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1 |
dwcontrol.Object.dwcontrolname.property |
You can use a DWObject variable to refer to dwcontrolname.
If the code declares a DWObject variable and assigns the control
within the DataWindow to the variable, using syntax like this:
|
1 2 |
DWObject dwobjectvar dwobjectvar = dwcontrol.Object.dwcontrolname |
the syntax of the expression itself becomes:
|
1 |
dwobjectvar.property |
For example, if the DataWindow had a column named empname, a text
control named t_emplabel, and a computed field named cf_average, you
could make the following assignments:
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1 2 3 4 |
DWObject dwo_column, dwo_text, dwo_compute dwo_column = dw_1.Object.empname dwo_text = dw_1.Object.t_emplabel dwo_compute = dw_1.Object.cf_average |
Data expressions
You can use a DWObject variable to refer to a column in a data
expression. For example, this syntax gets data for a single row and
column:
|
1 |
dwcontrol.Object.columnname {.buffer } {.datasource } [ rownum ] |
If the code declares a DWObject variable and assigns the control
within the DataWindow to the variable, using syntax like this:
|
1 2 |
DWObject dwobjectvar dwobjectvar = dwcontrol.Object.columnname |
The syntax of the expression itself becomes:
|
1 |
dwobjectvar. {.buffer } {.datasource } [ rownum ] |