c# - How to logout a user (with session) -

i wondering how log out user session in c# using asp.net. using sql server retrive users name when logged in, (2nd block of code below) directly below here code behind login button aspx page

protected void btnlogin_click(object sender, eventargs e) {         string email = txtemail.text;         string password = txtpassword.text;//aquire email , password , add strings          sqldatareader dataread = null;          sqlconn.open();         sqlcommand chklogin = new sqlcommand("select * member email='" + email + "' , password='" + password + "'", sqlconn);         dataread = chklogin.executereader();         sqlcommand nameadd = new sqlcommand("select name member email='" + email + "'", sqlconn);          if (dataread.read())         {             response.write("you logged in");              session.add("userid", dataread[0].tostring());             session.add("userfname", dataread[1].tostring());             session.add("useremail", dataread[3].tostring());              response.redirect("~/profiles.aspx");         }         else         {             response.write("please try again. usernames , passwords not match.");         }         sqlconn.close();     }  

when logged in redirected page. here code behind page

if (session.count > 0) {     if (session.count > 0)     {                 string name = (string)session["userfname"];                 txtgreeting.visible = true;                 txtgreeting.text = "welcome " + name + " , logged in! ";     } } 

you can use session.clear(); method when user clicks on logout button if have one.

and on method

if (session.count > 0) { if (session["username"] != null) {             string name = (string)session["userfname"];             txtgreeting.visible = true;             txtgreeting.text = "welcome " + name + " , logged in! "; } else{ response.redirect(logout.aspx); } } 

add 1 more condition check whether session has or not.