How to modify the Log On user for a windows service?

I have developed a windows service using with a small forms application to start it, stop it, and set it to auto-start with the operating system.

I need to be able to modify the security context for the service, which is available in the service properties under the Log On tab.

How do I do this?

Who is Participating?
grayeConnect With a Mentor Commented:
The Change() method of the Win32_Service class allows you to change both the Login User and Password

Yeah, I'll admit... this is a complicated example to use as your first introduction to WMI...
This is normally done from the "service installer" portion of your service.  Or, obviously, it can by using the control panel applet after the service is installed.

VB.Net has rather nice ServiceInstaller and ServiceProcessInstaller components for this purpose.   You can set the account in the ServiceProcessInstaller.
cressetAuthor Commented:
At present my forms application doesn't have a ServiceProcessInstaller.   I can start, stop, and set autostart on the service without one, although I'm happy to accept that I may be doing it wrong!   I'm trying to emulate the SQL Server Service Manager functionality just to make things easier for less computer literate users.  

Do this make a difference to your proposed solution?

Thanks for your help.

Free Tool: ZipGrep

ZipGrep is a utility that can list and search zip (.war, .ear, .jar, etc) archives for text patterns, without the need to extract the archive's contents.

One of a set of tools we're offering as a way to say thank you for being a part of the community.

OOOOohhhh... you're not writing the service itself.   You're writing a WinForm client application that will control the service?

If so, you can disregard the service-related gobbly-gook that I wrote about above.

The Dot Net Framework has a built-in ServiceController class that will do *some* of the thing you would typically expect...

        ' add a reference to System.ServiceProcess.dll
        Dim sc As ServiceController
        sc = New ServiceController("TermService", PC)

However, it wasn't desgined to change the "conditions" of the service, the "log on user", "start mode", etc.  For that, I'd recommend Windows Management Instrumentation (WMI).  Here is an example to demonstrate the concepts (it just changes the start mode).

        ' add a reference to System.Management
        Dim obj As ManagementObject
        Dim inParams, outParams As ManagementBaseObject

        obj = New ManagementObject("\\" & PC & "\root\cimv2:Win32_Service.Name='TermService'")

        ' change the Start Mode to Disabled
        If obj("StartMode") <> "Disabled" Then
            ' Get an input parameters object for this method
            inParams = obj.GetMethodParameters("ChangeStartMode")
            inParams("StartMode") = "Disabled"

            ' do it!
            outParams = obj.InvokeMethod("ChangeStartMode", inParams, Nothing)
            Result = Convert.ToInt32(outParams("returnValue"))
            If Result <> 0 Then
                Throw New Exception("ChangeStartMode method error code " & Result)
            End If
        End If
cressetAuthor Commented:
Jeez!   I think I'm going to scratch my head for a bit.   I've been setting the conditions for start mode by updating the registry directly.  

I think I might re-write that bit so it uses your method...

It's late.   I'll test this in the morning before awarding you hundreds of points and building a small shrine to your brilliance!

cressetAuthor Commented:
OK.   Had a good look at this.   While it allows you to change the username (and even set it to .\LocalSystem), there doesn't appear to be any mechanism for setting the password.  

I've found scripting examples from following the link you provided, but I can't see how they can be converted to visual basic.

Any further help gratefully received!
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

All Courses

From novice to tech pro — start learning today.