Process.MainWindowTitle returns empty used in Windows Service (OS=Windows7)

Question

Hi I have developed a Windows Service in VS2010 which is running on Windows7. I am trying to get  MainWindowTitle  but it returns empty. lObj_Process = Process .GetProcessById(Pi_ProcessID) lObj_Process.MainWindowTitle If same service runs on Windows XP title is found so it is not a Windows Service restriction. Moreover if I use the same code in windows application rather than service then it returns proper title. Please note that Service is reading/writing files so there should be no privileges issue. Question: Why MainWindowTitle property works fine for windows application but returns empty if used in Windows Service. Regards Immi

Vulpes · Answer

FWIW I can't see anything in the MSDN documentation about service changes in Vista or Windows 7 which would affect the ability to obtain this information. Basically you need the SeDebugPrivilege security privilege to read into another process's address space to obtain UI information which should automatically be available under the LocalSystem account. According to the documentation for the ServiceBase class a service you create using .NET runs by default under the System account. So unless you're using a different account which lacks this privilege under Windows 7 I don't know what the problem can be. To make absolutely sure you could try enabling this privilege manually using the code in this link ( http://rongchaua.net/blog/c-how-to-enable-sedebugprivilege/ ) and see whether it's any better.

Sam Hobbs · Answer

Immi can you do the research that you are are supposed to do? You should check the relevant documentation of updates. You should even if it is not directly relevant to this specific problem. I don't have a specific link but you should educate yourself about this.

Immi · Answer

Thanks for replies Vulpes  'Allow service to interact with desktop' is already checked for both Windows7 as well as Windows XP. Infact same service is tested for both OS. Any other suggestion plz? Sam Hobbs I got the title on WindowsXP thats why thought that it should not be a service restriction. I am not sure about this change for Windows 7. Infact my client is migrating to Windows 7 from WinXP. Same functionality was achieved earlier so i must have to achieve the functionity on Windows 7 as well in any case. a) Can you provide any authentic link which can clearly tell that it is not possible to get title (or UI properties) in service for Windows7? b) Is there any other solution for this like API or so? Regards Immi

Sam Hobbs · Answer

In the past Microsoft discouraged use of any UI for services. Later versions of Windows are now enforcing that policy; correct? So it seems to me that it is entirely possible that it is a Windows 7 Windows Service restriction. Are you sure you have looked at the changes for Windows 7?

Vulpes · Answer

OK I understand now what you're trying to do :) The only reason I can think of why the service doesn't show the window titles in Windows 7 is that you've omitted to tick the 'Allow service to interact with desktop' checkbox in the 'Log On' tab of your service's properties in the Management Console. Perhaps you remembered to do this in XP but not in Windows 7?

Immi · Answer

Thanks for reply Service has no UI and no main window. Infact Service is trying to get title of other running processes. These processes have UI and obviously titled main windows. Service get the process ID of these processes successfully. Also service can get the process name .i.e. lObj_Process = Process .GetProcessById(Pi_ProcessID) lObj_Process.ProcessName But lObj_Process.MainWindowTitle returns empty. It is obvious that running processes are not child process of service at all. I am repeating that i f same service runs on Windows XP title is found so it is not a Windows Service restriction in my case. Hope situation is clear now? Thanks and Regards Immi

Vulpes · Answer

I don't really understand how a service as such can have a window. If you're interacting with the desktop and starting a UI process from the service then the child process will have a main window and therefore a title. So can you clarify the position here please.