Storing Data in Web Storage - HTML5 Programming for ASP.NET Developers - page 197

Table 7-4. Keys Used in the JSON Dictionary

Key Value

FirstName A string value indicating the user's first name

LastName A string value indicating the user's last name

Email A string indicating the user's e-mail address

<choice_id> <question_id> An integer indicating the QuestionID of the choice: for example,

localStorage["3"] = 1 where 3 is a ChoiceID and 1 is a QuestionID

Note that localStorage is a key-value collection, and each key needs to be unique. Each choice in the
Choices table has a unique ChoiceID . That is why you make ChoiceID the key and QuestionID the value. If
you did it the other way around, you couldn't store multiple choices for a question—the latest ChoiceID
would overwrite the previously stored ChoiceID because the QuestionID for both would be the same.
Once SaveResults() returns successfully, all the data from localStorage is removed using the clear()
method. The SaveResults() action method that saves the survey results in the Results table is shown in
Listing 7-13.

Listing 7-13. SaveResults() Action Method
public JsonResult SaveResults()
{
string jsonData = string.Empty;
using (StreamReader sr = new StreamReader(Request.InputStream))
{
jsonData = sr.ReadToEnd();
}
Dictionary<string, string> data =
JsonConvert.DeserializeObject<Dictionary<string, string>>(jsonData);

SurveyDbEntities db = new SurveyDbEntities();

User usr = new User();
usr.FirstName = data["FirstName"];
usr.LastName = data["LastName"];
usr.Email = data["Email"];
db.Users.AddObject(usr);
db.SaveChanges();

string userEmail = data["Email"];
int usrId = (from item in db.Users
where item.Email == userEmail
select item.UserID).SingleOrDefault();

data.Remove("FirstName");
data.Remove("LastName");
data.Remove("Email");

foreach (string str in data.Keys)
{
int choiceId = int.Parse(str);