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I am implementing a Windows service in C#. This service calls a separate application that launches interactive windows. I have been able to work through the problems imposed by Session 0 Isolation by using the following series of steps:

  1. LogonUser() to get a logon token for the user who will execute the separate application
  2. SetTokenInformation() to transfer the user's logon token into session 1
  3. CreateProcessAsUser() to launch the application in the user's session.

This works; When the service launches the application, I see the application's windows appear in my console session. However, the application's windows have black backgrounds and all of the controls are invisible. If I click in an area where I know there is a button, the window responds, so it is clearly able to receive user input.

Here is (a simplified and stripped down version of) the code I'm using:

IntPtr logonToken;
LogonUser(username, domain, password, LOGON32_LOGON_INTERACTIVE, LOGON32_PROVIDER_DEFAULT, out logonToken);

SetTokenInformation(logonToken, TOKEN_INFORMATION_CLASS.TokenSessionId, sessionIdValuePtr, sessionIdSize);

STARTUPINFO startupinfo = new STARTUPINFO();
startupinfo.cb = Marshal.SizeOf(startupinfo);
startupinfo.lpDesktop = @"winsta0\default";

PROCESS_INFORMATION processinfo;
SECURITY_ATTRIBUTES processAttributes = new SECURITY_ATTRIBUTES();
SECURITY_ATTRIBUTES threadAttributes = new SECURITY_ATTRIBUTES();

ImpersonateLoggedOnUser(logonToken);

CreateProcessAsUser(
    logonToken, 
    null, 
    cmdLine, 
    ref processAttributes, 
    ref threadAttributes, 
    false, 
    0,
    IntPtr.Zero, 
    workingDirectory, 
    ref startupinfo, 
    out processinfo)

RevertToSelf();

I have tried adding code to load the user's profile before calling CreateProcessAsUser, but this did not help.

What could be causing the black backgrounds on my windows, and how should I go about fixing this problem? Any help would be most appreciated.

UPDATE: This appears to be very similar to the problem in this question: CreateProcessAsUser doesn't draw the GUI. He is using XP SP3, and I am having this problem in Windows 7 and Server 2008, meaning that I have the additional problem of dealing with Session 0 Isolation, but the symptoms in the two cases seem similar.

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Dave C
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    It's generally a bad idea to launch (or interact) with anything UI related from a windows service. When the actual user running the service isn't logged on your service will crash (hard). – riffnl Sep 21 '11 at 19:10
  • I understand the general reasons why one would not want to interact like this, and I agree. In this particular case, however, we are using a legacy application that throws up message boxes in certain rare conditions and we need to be able to gain access to them. I am handling the case when a user is not logged on by creating a WTS session for that user; when he logs on, he will see the message. – Dave C Sep 21 '11 at 19:18
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    possible duplicate of [CreateProcessAsUser doesn't draw the GUI](http://stackoverflow.com/questions/2584227/createprocessasuser-doesnt-draw-the-gui) – Hans Passant Sep 21 '11 at 20:18
  • Why not create a separate application that shares with the Service, a common data source (file, MSMQ, DB) for the messages. – Conrad Frix Sep 21 '11 at 21:23
  • @HansPassant: I had not seen that post before. The user is using XP SP3, however, and I'm using Win7/W2K8, and they're rather different in regards to session isolation. Thanks for the catch, though :) – Dave C Sep 22 '11 at 12:28
  • @ConradFrix: Unfortunately, we are stuck with this application the way it is. It's provided by another company, and they have not been willing to remove the offending prompt. Our long-term goal is to get rid of this application entirely, but for right now, this is what we have to work with. Like I said, for the most part it runs entirely silently, but there are a few weird cases where it throws up a prompt, and we have to be able to deal with it when that happens. – Dave C Sep 22 '11 at 12:31

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