/// <summary> /// Check username and password when user login to system /// </summary> /// <param name="loginModel">Username and password of user who want to login to system</param> /// <returns>return 0 if username and password are valid, return 1 if password is invalid, return -1 if all are invalid</returns> public int CheckLogin(string userName, string password) { LogManagementSystemEntities dbContext = new LogManagementSystemEntities(); var isExistUser = dbContext.Users.FirstOrDefault(x => x.UserName == userName && x.Password == password); if (isExistUser != null) { return(0); } else { return(-1); } }