How I can use sessions in my code using asp.net vb.net -

i want make sessions, don't know can start. logged in myself, without using session , have make sessions. below code have done far.

protected sub btnlogin_click(byval sender object, byval e eventargs) handles btnlogin.click      if txt_username.text = "" or txt_password.text = ""         error_usr_invalid.visible = false         if txt_username.text = ""             error_usr_blank.visible = true         elseif txt_username.text <> ""             error_usr_blank.visible = false         end if         if txt_password.text = ""             error_pwd_blank.visible = true         elseif txt_username.text <> ""             error_pwd_blank.visible = false         end if     elseif txt_username.text <> "" , txt_password.text <> ""         dim con new sqlconnection(configurationmanager.connectionstrings("connectionstring").connectionstring)         con.open()         dim cmd new sqlcommand("select * users username = '" + txt_username.text + "' , password = '" + txt_password.text + "'", con)         cmd.parameters.addwithvalue("@username", txt_username.text)         cmd.parameters.addwithvalue("@password", txt_password.text)         dim da new sqldataadapter(cmd)         dim dt new datatable()         da.fill(dt)         if dt.rows.count > 0             error_usr_invalid.visible = false             error_usr_blank.visible = false             error_pwd_blank.visible = false              response.redirect("main.aspx")         else             error_usr_invalid.visible = true             error_usr_blank.visible = false             error_pwd_blank.visible = false         end if     end if 

please me out suggesting ideas in code.

you can read session here : asp.net session state overview

now, there few examples :

add value session : session.add("username", txt_username.text)

get value session : dim username string = session("username")

for example : can store username session("username") , use on other page (for example in main.aspx) until remove it.

one more example :

default.aspx

protected sub btnlogin_click(byval sender object, byval e eventargs) handles btnlogin.click   session.add("username", txt_username.text)   response.redirect("main.aspx") end sub 

and in main.aspx :

protected sub page_load(byval sender object, byval e system.eventargs) handles me.load   label1.text = session("username") end sub 

session can used storing arrays, , other type of datas. example :

session.add("list", list(of string)) session("list").add("record #1") session("list").add("record #2") session("list").add("record #3") 

and use somewhere else :

for x = 0 session("list").count - 1   label1.text = session("list")(x) + ", " next 

remove session : session.remove("username") (this session item removed)

when finished work (for example log out), can remove, clear, abandon session.

session.removeall() : session.clear() : session.abandon()

you can store data session , use anywhere in web app.

btw. in code, little better approach :

dim con new sqlconnection(configurationmanager.connectionstrings("connectionstring").connectionstring) if con.state = connectionstate.open con.close() con.connectionstring = configurationmanager.connectionstrings("connectionstring").tostring con.open() dim cmd new sqlcommand("select * users username = @username , password = @password;", con) cmd.parameters.addwithvalue("@username", txt_username.text) cmd.parameters.addwithvalue("@password", txt_password.text) dim tds sqldatareader = cmd.executereader session.add("isexist", tds.hasrows)   'there example how store result session (in case result value true or false) tds.close(): cmd.dispose(): con.close()  'avoid connection stay opened if session("isexist") = true   'user successful log in, session("isexist") true   session.remove("isexist")   response.redirect("main.aspx") else   'username or password doesn't exist in database, session("isexist") false   session.remove("isexist")   'do want end if 

of course, have pay attention session timeout.... can read more provided link on start of post.