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Universal Trace Monitor for Software Developers and Testers

Using DevTracer with Visual Basic® for Applications

DevTracer is a replacement for the Debug.Print method in Visual Basic® for Applications. It is more flexible, because Debug.Print output is only visible inside the development environment in the immediate window. Once the application is compiled, it cannot be used any more.

Debug output generated with DevTracer can still be used once the application is compiled. Furthermore DevTracer provides two methods Write and WriteLine. WriteLine corresponds to Debug.Print. Write is similar, except that it does not append a newline character. Therefore the output of several calls to Write will be shown on the same line. DevTracer also has some support for formatting with methods Indent and Unindent.

The code encapsulates all calls to the COM-Component of DevTracer. Have a close look at method Init. It Instantiates the COM object, but tries only once. If this attempt fails, all calls to methods like WriteLine() will do nothing. Therefore the application will work on a computer without the COM-component installed, without any significant performance loss.


The methods WriteLine and Write are mapped to DoPrintLine and DoPrint respectively because Write is reserved in Visual Basic.

Just copy the following code to a module DEVTRACER.BAS :

Option Explicit

Private dev As Object
Private isInitialized  As Boolean ' VB6 initializes this to 'false'

Private Sub Init()
    If isInitialized = True Then
        Exit Sub   ' only try once to initialize COM object
    End If
    isInitialized = True
    On Error GoTo notFound
    Set dev = CreateObject("NRSoftware.DevTracer")
    dev.Init "localhost", 12345   ' set ip-adress and port
    dev.IndentSize = 2            ' set indent size

End Sub

Public Sub DoPrintLine(ByVal str As String)
    If dev Is Nothing Then Exit Sub
    dev.WriteLine str
End Sub

Public Sub DoPrint(ByVal str As String)
    If dev Is Nothing Then Exit Sub
    dev.Write str
End Sub

Public Sub Indent()
    If dev Is Nothing Then Exit Sub
End Sub

Public Sub Unindent()
    If dev Is Nothing Then Exit Sub
End Sub
DevTracer.bas Download

With this module added to your project, you can use DevTracer with code like:

devTracer.PrintLine "This is line 1"
devTracer.DoPrintLine "this is line 2 indented"
devTracer.DoPrintLine "this is line 3 even more indented"
devTracer.DoPrintLine "this is line 4, all indenting removed"


The example here uses late binding. It is also possible to work with early binding. But then the application will depend on DevTracer Component being installed on the computer running the application.

The image shows an example using DevTracer with Excel 2007 on Windows Vista, and the VBA code.

Example for using DevTracer with Microsoft Excel 2007 VBA coe for example for using DevTracer with Microsoft Excel 2007


DevTracer is based on the .NET Framework version 2.0. There are some compatibility issues with .NET version 2.0 and some older versions of Microsoft Office (Office 2003 and before) if the currently logged in user has administrator privileges. Normal uses (without administrator privileges) will not have this problem.

The problem is that it is not possible to create an instance of DevTracer Component. The sample code above (DEVTRACER.BAS) does not show any error, because the code demonstrates how to implement using DevTracer without making the application depending on it. Therefore the code above just will not work, i.e. no information will be displayed in DevTracer Monitor.

In this case please try the following code:

Dim devTracer
set devTracer = CreateObject ("NRSoftware.DevTracer")


and you may get the message

Automation error 80131700 when trying to instantiate DevTracer Component

If you get this message with the error number 80131700, please contact us or send a mail to . We can provide you with a different setup, which contains a fix from Microsoft.

This error does not occur with Office 2007 and Windows Vista.