How to get user groups without active directory...

Hello.

I need a list of grups (roles) of a logged user (without Active Directory)

I've been searching info about how to get groups that a user belongs to, and i've found this way to do it:

public static string[] groupList(System.Security.Principal.WindowsIdentity wId)
{
Type type = wId.GetType();
Object[] arr = new Object[] { wId.Token };
Object oRoles = type.InvokeMember("_GetRoles", BindingFlags.Static |
BindingFlags.InvokeMethod | BindingFlags.NonPublic, null, wId, arr);
return (string[])oRoles;
}

This code invokes to a static private member of the class WindowsIdentity (_GetRoles).

I do not like much this solution, because hacking .NET is not good ....

Do you know other way to get this information

Thanks.