ado.net - How to implement Sql helper class in asp.net -

sqlhelper.executenonquery(constring, commandtype.storedprocedure, "userregister_insert",                         new sqlparameter("@firstname",sqldbtype.nvarchar,50),                         new sqlparameter("@lastname",lastname),                         new sqlparameter("@email",email),                         new sqlparameter("@password",password),                         new sqlparameter("@contactno",contactno)); 

i have implemented sql helper class members of class unable access.

error @ connection string not defined in current context ?
please take string variable , initialize above code , try run it

string constring=system.configuration.configurationmanager.     connectionstrings["connectionstringname"].connectionstring;//your connection string name sqlhelper.executenonquery(constring, commandtype.storedprocedure, "userregister_insert",                         new sqlparameter("@firstname",sqldbtype.nvarchar,50),                         new sqlparameter("@lastname",lastname),                         new sqlparameter("@email",email),                         new sqlparameter("@password",password),                         new sqlparameter("@contactno",contactno));