Using a RichText DataWindow object
This section discusses:
- How scrolling differs
from other DataWindow styles - Problems you may encounter with default values for
new rows - What happens when the user makes changes
Scrolling
In a RichText DataWindow object, the rich text can consist
of more than one page. A row of data can be associated with several
pages, making a row larger than a page. In other DataWindow styles,
a page consists of one or more than one row–a page is larger
than a row.
For a RichText DataWindow object, the scrolling functions
behave differently because of this different meaning for a page:
- ScrollNextRow and ScrollPriorRow
still scroll from row to row so that another row’s data
is displayed within the document template - ScrollNextPage and ScrollPriorPage scroll among
pages of the document rather than pages of rows
Page flow As you scroll, the pages appear to flow from one row to the
next. Scrolling to the next page when you are on the last page of
the document takes you to the first page for the next row. The user
gets the effect of scrolling through many instances of the document.
New rows: default data and validation rules
Input fields are invisible when they have no value. Before
data is retrieved, PowerBuilder displays question marks (??) in fields
to make them visible. For new rows, PowerBuilder assigns an initial
value based on the data type.
If you have specified an initial value for the column, PowerBuilder uses
that value; but if no value is specified
, PowerBuilder uses
spaces for string columns or zero for numeric columns.
Possible validation errors If the default initial value provided by PowerBuilder does
not satisfy
the validation rule, the user gets a validation error
as soon as the new row is inserted. To avoid this, you should specify initial
values that meet your validation criteria.
When the user makes changes
Display only When you check Display Only on the General property page for
the Rich Text Object, the user cannot make any changes to the data
or the rich text.
If you leave the popup menu enabled, the user can turn off
the display-only setting and make the DataWindow object editable.
Input fields In an editable DataWindow object, users change the value of
a column input field by selecting it so that it flashes, pressing
the space bar to activate the input field and typing the new value.
They can also display the input field’s property sheet
and edit the Data Value textbox. For a computed field input field,
the Data Value textbox is read-only.
You can let the user display input field names instead of
data. You might do this if you were providing an editing environment
in which users were developing their own RichText DataWindow object.
However, the RichTextEdit control is better suited to a task like
this, because you have more scripting control over the user’s
options.
Rich text If users edit the text or formatting, they are changing the
document template. The changes are seen for every row.
The changes apply to that session only, unless you take extra
steps to save the changes and restore them.
To save the changes, you can write a script that uses the
CopyRTF function to get all the text, including the named input
fields but not the row data, and save the contents of that string
in a file or database. Whenever users view the RichText DataWindow
object, you can restore their latest version or let them return
to the original definition of the DataWindow object’s text.
Functions for RichText DataWindow objects
The DataWindow control has many functions.
Functions that behave the same DataWindow control functions that operate on data, such as
Update or Retrieve, have the same behavior for all types of DataWindow
objects.
When the object in the control is a RichText DataWindow object,
some of the functions do not apply or behave differently.
Functions that do not apply Some functions are not applicable when the object is a RichText
DataWindow object. They return an error or have no effect:
- Functions for graph
and crosstab DataWindow objects - Functions for grouping: GroupCalc, FindGroupChange
- Functions for code tables: GetValue, SetValue
- Functions for selecting rows: SelectRow, SetRowFocusIndicator, GetSelectedRow
- Functions that affect column and detail band appearance:
SetBorderStyle, SetDetailHeight - ObjectAtPointer
- OLEActivate
Functions that behave differently Some functions have different behavior when the object is
a RichText DataWindow object:
- Functions for the
clipboard: Copy, Clear, and so on - Functions for editable text (they apply to the edit
control in other DataWindow styles): LineCount, Position, SelectText,
and so on - Find and FindNext (the arguments you specify for
Find determine whether you want the general DataWindow Find function
or the RichText version) - Scrolling