Web Forms :: Display Online Users Except Current Logged In User In Membership

I have below code to display "list of all the online users" inside listBox using Membership function.

Code:

protected void Page_Load(object sender, EventArgs e) {
if (!IsPostBack) {
MembershipUserCollection allUser = Membership.GetAllUsers(); // to get all the users
List<MembershipUser> onlineUsers = new List<MembershipUser>(); //creating list of online users
foreach (MembershipUser user in allUser)

[Code] ....

I want to remove that user from the list of online users, who himself has logged in. Example: if I had logged-in with UserName: Admin, then this Admin should not show to me in the list of "online users"

Tried below Code but not working:

protected void Page_Load(object sender, EventArgs e) {
if (!IsPostBack) {
MembershipUserCollection allUser = Membership.GetAllUsers(); // to get all the users
List<MembershipUser> onlineUsers = new List<MembershipUser>(); //creating list of online users
MembershipUser m_user = Membership.GetUser(); //to get self logged-in user

[Code] ....