Using a RichTextEdit control – PB Docs 115

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Using a RichTextEdit control

A RichTextEdit control in a window or user object lets the
user view or edit formatted text. Functions allow you to manipulate
the contents of the control by inserting text, getting the selected
text, managing input fields, and setting properties for all or some
of the contents.

You define RichTextEdit controls in the Window painter or
the User Object painter.

Giving the user control

In the Window or User Object painter, on the Document page
of the RichTextEdit control’s property sheet, you can enable
or disable the features in Table 16-1.

Table 16-1: RichTextEdit control features
Features Details
Editing bars A toolbar for text formatting, a ruler
bar, and a status bar.
Pop-up menu Provides access to the InsertFile and
clipboard commands, as well as the property sheet.
Display of nonprinting characters Carriage returns, tabs, and spaces.
Display of fields Whether fields are visible at all, or
whether the field name or data displays. You can also change the
background color for fields.
Wordwrap Affects newly entered text only.

If the user enters new text in an existing paragraph, word wrap
is triggered when the text reaches the right edge of the control. To get existing text
to wrap within the display, the user can tweak the size of the control
(if it is resizable).
Print margins Print margins can be set relative to
the default page size.

You can also specify a name for the document that is displayed
in the print queue. The document name has nothing to do with a text
file you might insert in the control.

Users can change the available tools

When users display the property sheet for the rich text document,
they can change the tools that are available to them, which you
might not want. For example, they might:

  • Remove the display-only setting so that they can
    begin editing a document you set up as protected
  • Turn off the tool, ruler, or status bars
  • View input fields’ names instead of data
  • Disable the pop-up menu so that they cannot restore
    tools they turn off

You might want to guard against some of these possibilities.
You can reset the property values for these settings in a script.
For example, this statement restores the pop-up menu when triggered
in an event script:

Undoing changes

The user can press Ctrl+Z to undo a change. You can
also program a button or menu item that calls the Undo function.

If Undo is called repeatedly, it continues
to undo changes to a maximum of 50 changes. The script can check
whether there are changes that can be undone (meaning the maximum
depth has not been reached) by calling the CanUndo function:

Text for the control

In the Window painter, you do not enter text in the control.
Instead, in your application you can programmatically insert text
or let the user enter text using the editing tools.

note.gif Setting a default font The Font tab page in the Properties view for a RichTextEdit
control lets you set default font characteristics for the control.
When the control first displays at runtime, and you include the
toolbar with a RichTextEdit control, the toolbar indicates the default
font characteristics that you selected on the Font tab page at design
time. Although the application user can change fonts at runtime,
or you can use PowerScript to change the font style, you can set
the default font at design time only.

Inserting text

From a file If you have prepared a text file for your application, you
can insert it with the InsertDocument function.
The file can be rich text or ASCII:

The boolean clearflag argument lets you
specify whether to insert the file into existing text or replace
it. If you want to include headers and footers from a document that
you insert, you must replace the existing text by setting the clearflag argument
to TRUE. (The InsertFile command
on the runtime pop-up menu is equivalent to the InsertDocument function
with the clearflag argument set to FALSE.)

note.gif DisplayOnly property must be set to false You cannot insert a document into a rich text control when
the control’s DisplayOnly property is set to true. If you
try to do this, PowerBuilder displays a runtime error message.

From a database If you have saved rich text as a string in a database, you can
use a DataStore to retrieve the text.

After retrieving data, paste the string into the RichTextEdit
control:

note.gif Rich text and the clipboard The CopyRTF and PasteRTF functions
let you get rich text with formatting instructions and
store it in a string. If you use the clipboard by means of the Copy, Cut,
and Paste functions, you get the text only—the
formatting is lost.

Example of saving rich text in a database

Suppose you have a database table that records tech support
calls. Various fields record each call’s date, support
engineer, and customer. Another field stores notes about the call.
You can let the user record notes with bold and italic formatting
for emphasis by storing rich text instead of plain text.

The window for editing call information includes these controls:

  • A DataWindow control that
    retrieves all the data and displays everything except the call notes
  • A RichTextEdit control that displays the call notes
  • A button for updating the database

RowFocusChanged event As row focus changes, the notes for the current row are pasted
into the RichTextEdit control. The RowFocusChanged event has this
script:

LoseFocus event When the user makes changes, the changes are transferred to
the DataWindow control. It is assumed that the user will click on
the button or the DataWindow control when the user is through editing,
triggering the LoseFocus event, which has this script:

note.gif LoseFocus and the toolbars A LoseFocus event occurs for the RichTextEdit control even
when the user clicks a RichTextEdit toolbar. Technically, this is
because the toolbars are in their own windows. However, the RichTextEdit
control still has focus, which you can check with the GetFocus function.

Saving rich text in a file

You can save the rich text in the control, with the input
field definitions, with the SaveDocument function.
You have the choice of rich text format (RTF) or ASCII:

SaveDocument does not save the data in
the input fields. It saves the document template.

Does the file exist? If the file exists, calling SaveDocument triggers
the FileExists event. In the event script, you might ask users if
they want to overwrite the file.

To cancel the saving process, specify a return code of 1 in
the event script.

Are there changes that need saving? The Modified property indicates whether any changes have been
made to the contents of the control. It indicates that the contents
are in an unsaved state. When the first change occurs, PowerBuilder
triggers the Modified event and sets the Modified property to TRUE.
Calling SaveDocument sets Modified to FALSE,
indicating that the document is clean.

Opening a file triggers the Modified event and sets the property
because the control’s contents changed. Usually, though,
what you really want to know is whether the contents of the control
still correspond to the contents of the file. Therefore, in the
script that opens the file, you can set the Modified property to FALSE yourself.
Then when the user begins editing, the Modified event is triggered
again and the property is reset to TRUE.

Opening and saving files: an example

This example consists of several scripts that handle opening
and saving files. Users can open existing files and save changes.
They can also save the contents to another file. If users save the
file they opened, saving proceeds without interrupting the user.
If users save to a file name that exists, but is not the file they
opened, they are asked whether to overwrite the file:

dartsave.gif

The example includes instance variable declarations, scripts,
functions, and events.

Instance variable declarations

ib_saveas A flag for the FileExists event. When FALSE,
the user is saving to the file that was opened, so overwriting is
expected:

is_filename The current file name for the contents, initially set to “Untitled”:

Open Document script

This script opens a file chosen by the user. Since opening
a file triggers the Modified event and sets the Modified property,
the script resets Modified to FALSE. The Checked
property of the Modified check box is set to FALSE too:

Scripts that save the document

The user might choose to save the document to the same name
or to a new name. These scripts could be assigned to menu items
as well as buttons. The Save button script checks whether the instance
variable is_filename holds a valid
name. If so, it passes that file name to the of_save function.
If not, it triggers the SaveAs button’s script instead:

The SaveAs script sets the instance variable ib_saveas so
that the FileExists event, if triggered, knows to ask about overwriting
the file. It calls of_getfilename to
prompt for a file name before passing that file name to the of_save function.

Functions for saving and getting a file name

of_save function This function accepts a file name argument and saves the document.
It updates the file name instance variable with the new name and sets
the check box to correspond with the Modified property, which is automatically
set to FALSE after you call SaveDocument successfully:

of_getfilename function The function prompts the user for a name and returns the file
name the user selects. It is called when a file name has not yet been
specified or when the user chooses Save As. It returns a file name:

Events for saving and closing

FileExists event When the user has selected a file name and the file already exists,
this script warns the user and allows the save to be canceled. The
event occurs when SaveDocument tries to save
a file and it already exists. The script checks whether ib_saveas is TRUE and,
if so, asks if the user wants to proceed with overwriting the existing
file:

Modified event This script sets a check box so the user can see that changes have
not been saved. The Modified property is set automatically when
the event occurs. The event is triggered when the first change is
made to the contents of the control:

CloseQuery event This script for the window’s CloseQuery event checks whether
the control has unsaved changes and asks whether to save the document
before the window closes:

Using an ActiveX spell checking control

ActiveX controls
can be used to spell check text in a RichTextEdit control. The supported
ActiveX spell checking controls include VSSpell from ComponentOne
and WSpell from Wintertree Software.

You can use the SelectedStartPos and SelectedTextLength properties
of the RichTextEdit control to highlight the current position of
a misspelled word in a text string that you are parsing with a supported
ActiveX spell checking control. The following procedure uses an
ActiveX control to spell check the entire text of the current band
of a RichTextEdit control.

proc.gif To spell check selected text in a RichTextEdit
control:

  1. On a window with a RichTextEdit control,
    select Insert>Control>OLE from the window menu.

  2. Click the Insert Control tab of the Insert Object
    dialog box, select the installed ActiveX spell checking control,
    and click OK.

  3. Click inside the window in the Window painter
    to insert the ActiveX control.

    By default, the name of the inserted control is ole_n,
    where n = 1 when there are no other
    OLE controls on the window.

  4. Add a menu item to a menu that you associate with
    the current window and change its Text label to Check
    Spelling    .

  5. Add the following code the the Clicked event of
    the menu item, where windowName is the name
    of the window containing the RichTextEdit and ActiveX controls:

  6. Select the ActiveX control in the Window painter
    and select ReplaceWord from the event list for the control.

  7. Add the following code to the ReplaceWord event
    script:

    The next time you run the application, you can click the Check
    Spelling menu item to spell check the entire contents of the current
    band of the RichTextEdit control.

Formatting of rich text

In a RichText control, there are several user-addressable
objects:

  • The whole document
  • Selected text and paragraphs
  • Input fields
  • Pictures

The user can make selections, use the toolbars, and display
the property sheets for these objects.

Input fields get values either because the user or you specify
a value or because you have called DataSource to
associate the control with a DataWindow object or DataStore.

Input fields

An input field is a named value. You name it and you determine
what it means by setting its value. The value is associated with
the input field name. You can have several fields with the same
name and they all display the same value. If the user edits one
of them, they all change.

In this sample text, an input field for the customer’s
name is repeated throughout:

  • Hello {customer}!
  • We know that you, {customer},
    will be excited about our new deal. Please call soon, {customer},
    and save money now.

In a script, you can set the value of the customer field:

Then the text would look like this:

  • Hello Mary!
  • We know that you, Mary, will be excited about our
    new deal. Please call soon, Mary, and save money now.

The user can also set the value. There are two methods:

  • Selecting it and typing
    a new value
  • Displaying the Input Field property sheet and editing
    the Data Value text box

Inserting input fields in a script The InputFieldInsert function inserts a
field at the insertion point:

In a rich text editing application, you might want the user
to insert input fields. The user needs a way to specify the input
field name.

In this example, the user selects a name from a ListBox containing
possible input field names. The script inserts an input field at
the insertion point using the selected name:

Input fields for dates and page numbers

To display a date or a page number in a printed document,
you define an input field and set the input field’s value.

proc.gif To include today’s date in the opening
of a letter, you might:

  1. Create an input field in the text. Name
    it anything you want.

  2. In the script that opens the window or some other
    script, set the value of the input field to the current date.

For example, if the body of the letter included an input field
called TODAY, you would write a script like
the following to set it:

For information about setting page number
values see “What the user sees”.

Using database data

You can make a connection between a RichTextEdit control and
a DataWindow control or DataStore object. When an input field in
the RichTextEdit control has the same name as a column or computed
column in the DataWindow object, it displays the associated data.

Whether or not the RichTextEdit control has a data source,
there is always only one copy of the rich text
content. While editing, you might visualize the RichTextEdit contents
as a template into which row after row of data can be inserted.
While scrolling from row to row, you might think of many instances of
the document in which the text is fixed but the input field data
changes.

To share data between a DataWindow object or DataStore, use
the DataSource function:

Example of sharing data

If the DataWindow object associated with the DataStore ds_empdata has
the four columns emp_id, emp_lname, emp_fname,
and state, the RichTextEdit content might include
text and input fields like this:

note.gif Sample letter with columns from the employee table ID: {emp_id}

Dear {emp_fname} {emp_lname}:
We are opening a new plant in Mexico. If you would like to
transfer from {state} to
Mexico, the company will cover all expenses.

Navigating rows and pages

For the RichTextEdit control, navigation keys let the user
move among the pages of the document. However, you must provide
scrolling controls so that the user can move from row to row.

You should provide Prior Row and Next Row buttons. The scripts
for the buttons are simple. For Next Row:

For Prior Row:

If you also provide page buttons, then when the user is on
the last page of the document for one row, scrolling to the next
page moves to the first page for the next row:

Cursor position in the RichTextEdit control

Functions provide several ways to find out what is selected
and to select text in the RichTextEdit control.

Where is the insertion point or what is selected?

The text always contains an insertion point and it can contain
a selection, which is shown as highlighted text. When there is a
selection, the position of the insertion point can be at the start
or the end of the selection, depending on how the selection is made.
If the user drags from beginning to end, the insertion point is
at the end. If the user drags from end to beginning, the insertion
point is at the beginning.

The Position function provides information about the selection
and the insertion point.

For more information, see Position in the PowerScript
Reference
.

Changing the cursor image

The Pointer page of the Rich Text Object property sheet has
a list box with stock pointers that can be used to indicate cursor
position in a RichTextEdit control or RichText DataWindow. Users
can change the cursor image at runtime by selecting one of these
pointers and clicking OK in the Rich Text Object property sheet.

Selecting text programmatically

There are several functions that select portions of the text
relative to the position of the insertion point:

  • SelectTextWord
  • SelectTextLine
  • SelectTextAll

A more general text selection function is SelectText.
You specify the line and character number of the start and end of
the selection.

Passing values to SelectText Because values obtained with Position provide more information
than simply a selection range, you cannot pass the values directly
to SelectText. In particular, zero is not a valid
character position when selecting text, although it is meaningful
in describing the selection.

For more information, see Position in the PowerScript
Reference
.

For an example of selecting words one by one
for the purposes of spell checking, see the SelectTextWord function
in the PowerScript Reference
.

Tab order, focus, and the selection

Tab order For a window or user object, you include the RichTextEdit
control in the tab order of controls. However, after the user tabs
to the RichTextEdit control, pressing the tab key
inserts tabs into the text. The user cannot tab out to other controls.
Keep this in mind when you design the tab order for a window.

Focus and the selection When the user tabs to the RichTextEdit control, the control
gets focus and the current insertion point or selection is maintained.
If the user clicks the RichTextEdit control to set focus, the insertion
point moves to the place the user clicks.

LoseFocus event When the user clicks on a RichTextEdit toolbar, a LoseFocus
event occurs. However, the RichTextEdit control still has focus. You
can check whether the control has lost focus with the GetFocus function.

Preview and printing

The user can preview the layout and print the contents of
the RichTextEdit control. In print preview mode,
users see a view of the document reduced so that it fits inside
the control. However, you must set the print margins and page size
before you display the control in print preview mode.

There are two ways to enter print preview mode:

  • The user can press ctrl+f2 to
    switch between editing and print preview mode
  • You can call the Preview function
    in a script:

Users can page through the control contents in print preview
mode by using the up arrow and down arrow keys or the Page Up and
Page Down keys.

Adjusting the print margins

If you set page
margins at design time, or enable headers and footers for a rich text
control, application users can adjust the margins of the control
at runtime. Users can do this by opening the property sheet for
the RichTextEdit control to the Print Specifications tab and modifying
the left, right, top, or bottom margins, or by triggering an event
that changes the margins in PowerScript code. Adjusting the margins
in the Rich Text Object dialog box also affects the display of the
RichTextEdit control content in print preview mode.

If you do not set page margins at design time or leave them
at 0, any changes the user makes to the margins at runtime are visible
in print preview mode only.

dartprt.gif

note.gif Setting page size and orientation You cannot set the default page size and page orientation
at design time. However, users can set these properties at runtime
from the Print Specifications tab of the Rich Text Object dialog
box. This dialog box is available from the standard view only. You
must also enable the pop-up menu on a RichTextEdit control to enable
application users to display this dialog box.

Printing

If the RichTextEdit is using DataWindow object data, you can
limit the number of rows printed by setting the Print.Page.Range
property for the DataWindow control. Its value is a string that
lists the page numbers that you want to print. A dash indicates
a range.

Example of a page range Suppose your RichTextEdit control has a data source in the
control dw_source. Your rich text
document is three pages and you want to print the information for
rows 2 and 5. You can set the page range property before you print:

You can also filter or discard rows so that they are not printed.

For more information, see the SetFilter, Filter, RowsMove,
and RowsDiscard functions in the PowerScript
Reference
and the Print DataWindow object property in
the DataWindow Reference
.

Inserting footer text programmatically

This sample code sets the insertion point in the footer and
inserts two blank lines, text, and two input fields:

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Powerbuilder Documentation 11.5
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August 3, 2023
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