c# - "ExecuteReader: Connection property has not been initialized." -

i'm beginner in using asp.net mvc5, doing project.

it referring "var reader = cmd.executereader();" here code:

public bool isvalid(string username, string password) {     string constring = "server= ej ; database=onlineshopdb ; integrated security=sspi";      sqlcommand cmd = new sqlcommand("select * dbo.usertb username=@username , password=@password");     sqlconnection con = new sqlconnection(constring);      cmd.parameters.addwithvalue("@username", sqldbtype.varchar).value = username;     cmd.parameters.addwithvalue("@password", sqldbtype.varchar).value = password;     con.open();     var reader = cmd.executereader();      if (reader.hasrows)     {         reader.dispose();         cmd.dispose();         return true;     }     else     {         reader.dispose();         cmd.dispose();         return false;     } } 

wrap connection in using statement, , pass in second parameter of sqlcommand constructor:

var query = "select * whatever"; using(var con = new sqlconnection(constring)) using(var cmd = new sqlcommand(query, con)) {     con.open();     // etc }