void regenerateId(){    System.Web.SessionState.SessionIDManager manager = new System.Web.SessionState.SessionIDManager();    string oldId = manager.GetSessionID(Context);    string newId = manager.CreateSessionID(Context);    bool isAdd = false, isRedir = false;    manager.SaveSessionID(Context, newId, out isRedir, out isAdd);    HttpApplication ctx = (HttpApplication)HttpContext.Current.ApplicationInstance;    HttpModuleCollection mods = ctx.Modules;    System.Web.SessionState.SessionStateModule ssm = (SessionStateModule)mods.Get("Session");    System.Reflection.FieldInfo[] fields = ssm.GetType().GetFields(BindingFlags.NonPublic | BindingFlags.Instance);    SessionStateStoreProviderBase store = null;    System.Reflection.FieldInfo rqIdField = null, rqLockIdField = null, rqStateNotFoundField = null;    foreach (System.Reflection.FieldInfo field in fields)    {        if (field.Name.Equals("_store")) store = (SessionStateStoreProviderBase)field.GetValue(ssm);        if (field.Name.Equals("_rqId")) rqIdField = field;        if (field.Name.Equals("_rqLockId")) rqLockIdField = field;        if (field.Name.Equals("_rqSessionStateNotFound")) rqStateNotFoundField = field;    }    object lockId = rqLockIdField.GetValue(ssm);    if ((lockId != null) && (oldId !=null)) store.ReleaseItemExclusive(Context, oldId, lockId);    rqStateNotFoundField.SetValue(ssm, true);    rqIdField.SetValue(ssm, newId);}

来源http://stackoverflow.com/questions/1368403/generating-a-new-asp-net-session-in-the-current-httpcontext/4420114#4420114