public HttpResponseMessage Put([Bind(Include = "Email,Model")] TeacherViewModel tvm) { AssignmentManagementSystemEntities db = new AssignmentManagementSystemEntities(); var student = teaDB.ListAll().Find(t => t.Id.Equals(tvm.Id)); string message = "Teacher Updated Successfully"; tblTeacher tb = db.tblTeachers.Where(t => t.Teacher_Id == tvm.Id).FirstOrDefault(); bool isexists = teaDB.EmailExists(tvm.Email); if (isexists) { if (tb.Email == tvm.Email) { if (ModelState.IsValid) { teaDB.Update(tvm); return(Request.CreateResponse(HttpStatusCode.OK, message)); } else { return(Request.CreateErrorResponse(HttpStatusCode.BadRequest, ModelState)); } } else { ModelState.AddModelError("Email", "Email Already Exist"); } } if (ModelState.IsValid) { teaDB.Update(tvm); return(Request.CreateResponse(HttpStatusCode.OK, message)); } else { return(Request.CreateErrorResponse(HttpStatusCode.BadRequest, ModelState)); } }