Question

I have this code:

    [PermissionSet(SecurityAction.Assert, Name = "FullTrust")]
    public List<WinInfo> GetWindows()
    {
        try
        {
            var isFullTrust = Assembly.GetExecutingAssembly().IsFullyTrusted;
            if (isFullTrust)
            {
                return Process.GetProcesses().Where(z => !string.IsNullOrEmpty(z.MainWindowTitle))
                    .Select(z => new WinInfo
                        {
                            ProcessID = z.Id,
                            ProcessName = z.ProcessName,
                            WinID = z.MainWindowHandle,
                            WindowTitle = z.MainWindowTitle
                        }).ToList();
            }
            else
                return null;
        }
        catch (Exception ex)
        {
            Trace.Write(ex.Message);
            return null;
        }
    }

When I test in on my local computer under my current user (with admin rights) it works ok, displaying all the processes, that have windows. But when I call this code from a windows service, run under “Local Service” account, then the list is empty. I attached to the process, and through debug I found that “Process.GetProcesses()” returns all the processes, but all of them have MainWindowHandle as 0 and MainWindowTitle as empty, even when they do have windows. So what is wrong with my code?

Edit I edited code, so that it checks the assembly for full trust and have PemmissionSet that should grant the code the neccessary rights. Still the result is the same. When I debug, I can see, that “isFullTrust” is “True” and code executes with no exceptions. Still the list is empty, because none of the processes contains not-empty MainWindowTitle

Answer 1

According to this thread :

The problem you’re seeing is because by default service don’t have access to any interactive desktops. I don’t recommend interacting with the desktop from a service (#1, there may not be any desktop, #2 there may be multiple desktops, #3 interacting with the desktop from service in Vista is not implemented) but, you can check the “Interace with desktop” in your services properties.

maybe you can try to create an hidden form?