Syntax for one or all data items in a named column
Description
A DataWindow data expression can access a single item in a
column or computed field when you specify the control name and a
row number. It accesses all the data in the column when you omit
the row number.
Syntax
|
1 |
<span>dwcontrol</span>.Object.<span>columnname</span> {.<span>buffer</span> } {.<span>datasource</span> } { [<span> rownum </span>] } |
|
Parameter |
Description |
|---|---|
|
dwcontrol |
The name of the DataWindow control or |
|
columnname |
The name of a column or computed field |
|
buffer |
The name of the buffer from which you
|
|
datasource |
The source of the data. Values are:
|
|
rownum |
The row number of the desired item. The To access all the data in the column, omit rownum.  When buffer or datasource is not optional
When rownum is omitted, you must specify |
Return value
The expression has a datatype of Any. The expression returns
a single value (for a specific row number) or an array of values
(when rownum is omitted). Each value has a
datatype of columnname.
Usage
Is the expression a DWObject or data?
When you want to access all the data in the column, remember
to specify at least one of the other optional parameters. Otherwise,
the expression you specify refers to the column control, not
its data. This expression refers to the DWObject empname, not the
data in the column:
|
1 |
dw_1.Object.empname |
In contrast, these expressions all refer to data in the empname
column:
|
1 |
dw_1.Object.empname.Primary // All rows |
|
1 |
dw_1.Object.empname[5]      // Row 5 |
Row numbers for computed fields
When you refer to a control in a band other than the detail
band (usually a computed field) you still specify a row number.
For the header, footer, or summary, specify a row number of 1. For
the group header or trailer, specify the group number:
|
1 |
dw_1.Object.avg_cf[1] |
If you specify nothing after the computed field name, you
refer to the computed field DWObject, not the data. For a computed
field that occurs more than once, you can get all values by specifying buffer or datasource instead
of rownum, just as for columns.
When the expression is an array
When the expression returns an array (because there is no
row number), you must assign the result to an array, even if you
know there is only one row in the result.
This expression returns an array, even if there is only one
row in the DataWindow control:
|
1 |
dw_1.Object.empname.Primary |
This expression returns a single value:
|
1 |
dw_1.Object.empname[22] |
Examples
Because the default setting is current values in the primary
buffer, the following expressions are equivalent—both get
the value in row 1 for the emp_name column:
|
1 |
dw_1.Object.emp_name[1] |
|
1 |
dw_1.Object.emp_name.Primary.Current[1] |
This statement sets the emp_name value in row 1 to
Wilson:
|
1 |
dw_1.Object.emp_name[1] = "Wilson" |
This statement gets values for all the emp_name values
that have been retrieved and assigns them to an array of strings:
|
1 |
string ls_namearray[] |
|
1 |
ls_namearray = dw_1.Object.emp_name.Current |
This statement gets current values of emp_name from
all rows in the filter buffer:
|
1 |
string ls_namearray[] |
|
1 |
ls_namearray = dw_1.Object.emp_name.Filter |
This statement gets original values of emp_name from
all rows in the filter buffer:
|
1 |
string ls_namearray[] |
|
1 |
ls_namearray = dw_1.Object.emp_name.Filter.Original |
This statement gets the current value of emp_name
from row 14 in the delete buffer:
|
1 |
string ls_name |
|
1 |
ls_name = dw_1.Object.emp_name.Delete[14] |
This statement gets the original value of emp_name
from row 14 in the delete buffer:
|
1 |
string ls_name |
|
1 |
ls_name = dw_1.Object.emp_name.Delete.Original[14] |
This statement gets all the values of the computed field review_date:
|
1 |
string ld_review[] |
|
1 |
ld_review = dw_1.Object.review_date.Original |