Determining your Terminal Server Session ID from C#

I ran into an interesting .NET Remoting problem yesterday: Users on Terminal Services were stomping on each other running an app with a "private" remoting server that hadn't taken into account the possibility that multiple user could be trying to run it simultaneously on the same computer.

So the next question became: How do we uniquely identify separate instances on the same server? The quick answer was username, but that would fail if a user had multiple terminal server sessions. The better answer was to use the terminal server session id. Here's a code sample to determine your session id:

[DllImport("kernel32.dll")]

static extern bool ProcessIdToSessionId(uint dwProcessId, out uint pSessionId);

static void Main(string[] args)

{

Process _currentProcess = Process.GetCurrentProcess();

uint _processID = (uint)_currentProcess.Id;

uint _sessionID;

bool _result = ProcessIdToSessionId(_processID, out _sessionID);

Console.WriteLine("ProcessIdToSessionId Result: " + _result.ToString());

Console.WriteLine("Process ID = " + _processID.ToString());

Console.WriteLine("Session ID = " + _sessionID.ToString());

Console.ReadLine();

}

Notes:

1. On a standalone workstation the session id is zero (0).
2. The console session on a server is also zero (0).