FIX: Printer Error When Printing from RTF Control

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.