asp.net mvc 4 - Having error in updating my record in database my method as follows -

what have done wrong in code ? (i using mvc4 , ef) example: please clear fresher use mvc4

editresponse response = new editresponse(); try {     using (wematchcontext db = new wematchcontext())     {         b_member_register update = new b_member_register();         var output = db.b_member_register.where(x => x.member_id == model.member_id).firstordefault();         if(output != null )         {         update.first_name = model.first_name;         update.last_name = model.last_name;         update.gender = model.gender;         update.dob = model.dob;          int resultcount = db.savechanges();                             if (resultcount > 0)         {             response.member_id = update.member_id;             response.resultcode = 0;             response.message = "updated successfully";          }                  

you have attach updated data db entity. please try this,

using (wematchcontext db = new wematchcontext()) {             var update = db.b_member_register.where(x => x.member_id == model.member_id).firstordefault();     if(update != null )     {         update.first_name = model.first_name;         update.last_name = model.last_name;         update.gender = model.gender;         update.dob = model.dob;           //below line of code important.          db.b_member_register.attach(update);         db.entry(update).state = entitystate.modified;          int resultcount = db.savechanges();                             if (resultcount > 0)         {              response.member_id = update.member_id;              response.resultcode = 0;              response.message = "updated successfully";             }    } }