Q142290: FIX: Printer Error When Printing from RTF Control

Article: Q142290
Product(s): Microsoft Visual Basic for Windows
Version(s): 4.00
Operating System(s): 
Keyword(s): kbGrpDSVB
Last Modified: 11-JAN-2001

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The information in this article applies to:

- Microsoft Visual Basic Standard Edition, 32-bit, for Windows, version 4.0 
- Microsoft Visual Basic Professional Edition, 32-bit, for Windows, version 4.0 
- Microsoft Visual Basic Enterprise Edition, 32-bit, for Windows, version 4.0 
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SYMPTOMS
========

After printing from a Rich Text Box control, Visual Basic 4.0 raises error 482 -
"Printer Error". This error can occur when exiting a Visual Basic application or
when executing the EndDoc method of the Printer object.

RESOLUTION
==========

After printing from a RTF control, executing an EndDoc will exhibit this
problem. Visual Basic executes an automatic Printer.EndDoc if a program stops
execution with buffered data. Even though this error is raised, the pages do
print correctly. The workaround for this problem is to trap error 482 and simply
ignore it. The example below contains code to demonstrate this technique.

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article. This bug has been fixed in Visual Basic 5.0.


MORE INFORMATION
================

Steps to Reproduce
------------------

1. Start Visual Basic, or, if it is already running, choose New Project from the
  File Menu.

2. Add an RTF control and a command button to the form.

3. Insert the following code in the Command1_Click event.

     Private Sub Command1_Click()
         Printer.Print ""
         RichTextBox1.SelPrint Printer.hDC
         Printer.EndDoc
     End Sub

4. Run the application.

5. Enter some text in the RTF text box, and click on the command button to
  print. The program will stop and an error dialog box, complaining of the
  above mentioned error, will be displayed. Clicking on the "Debug" button in
  the error dialog box will show that the line of code that execution stopped
  on was the call to EndDoc.

This problem can be avoided by changing the code in the Command1_Click procedure
to the following:

     Private Sub Command1_Click()
         Printer.Print ""
         RichTextBox1.SelPrint Printer.hDC

         On Error GoTo EndDocError
         Printer.EndDoc
         On Error GoTo 0

         Exit Sub

     EndDocError:
         If Err.Number = 482 Then
             'do nothing
         Else
             Err.Raise Err.Number
         End If
     End Sub

This code initializes the printer object and prints from the RTF control. Error
trapping is turned on, and if the error that occurs with the EndDoc method is
number 482, it is ignored. If some other error is raised as a result of the
EndDoc method, that error is passed upwards in the call stack to be handled by
another procedure or Visual Basic as normal.

Additional Note
---------------

The RTF sample application included with the Visual Basic 4.0 MSDN Starter Kit
was written using a different version of the RTF control than the one that
shipped with Visual Basic 4.0. As a result, the above fix is not implemented in
the code for that sample application. The RTF sample can be fixed by the same
method outlined above; simply trap error 482 and ignore it.

Additional query words: kbVBp400bug kbVBp500fix kbVBp kbdsd kbDSupport kbPrint kbControl

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Keywords          : kbGrpDSVB 
Technology        : kbVBSearch kbAudDeveloper kbVB400Search kbVB400
Version           : 4.00
Issue type        : kbbug
Solution Type     : kbfix

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