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Save and retrieve Wrong Value From Json Object Items to IShared Preference in Xamarin.Android (Always Returns Logout Value)

I am developing a login application which save username and password using Shared Preferences in Xamarin Android (C#). Firstly, I get the username and password value from web service and then I check the value. If in my local db (sqlite) doesn't have the value so, I update the data with the newest one from web service. After that, I store the user ID by using my custom sqlite function to get the user ID with username and password.
So far, I can parse the Json Object from my web service and assign them into variables. But, I found something strange that, my parsed json object item can't be saved in my shared preferences. I've been 3 days searching and researching from internet but, I didn't find anything. I almost give up, guys. Would you like to help me? I would appreciate the helps.
Here what I did to my app.
I made utilities folder which save my essentials class. I made LoginSession class which save property of user now.
in my main activity
private void MyBtnLogin(object aSender, System.EventArgs e)
{
try
{
System.Net.Http.HttpClient client= new System.Net.Http.HttpClient();
System.Threading.Tasks.Task.Run(async () =>
{
string response = await _httpClient.GetStringAsync($"http://yourjson.com/{fix_email_value}");
JObject parsedObject = JObject.Parse(response);
int userID = parsedObject .Value<int>("ID");
string userEmail = _parsedResponseObject.Value<string>("Email");
string userPassword = _parsedResponseObject.Value<string>("Password");
List<User> lists= User.GetUserList(userID);
User updatedvalue= (from a in lists where a.Email == userEmail && a.Password == userPassword select a).FirstOrDefault();
if (updatedvalue== null)
{
updatedvalue= new User();
updatedvalue.ID = userID;
updatedvalue.Email = userEmail;
updatedvalue.Password = userPassword;
updatedvalue.StoreOrChange();
RunOnUiThread(() =>
{
SharedPref.UserIDNow= userID;
LoginSession.UserNow= User.GetID(userID);
});
} }
});
StartActivity(typeof(NextPage));
Finish();
}
and I retrieve the value in the next activity using SharedPref.UserIDNow to retrieve the user ID. I put the SharedPref.UserIDNow inside my static function to get current User ID
What am i missing? Everytime when I launch and login, after login the app closed like log out! and the value returns -22. Btw, -22 is a default value of my shared preference. I think it must be the ID of the User. Please help me :(

I test with your code , it works with no problem .
Some suggestions to troubleshoot .
Debug your code (add breakpoint) to check if SharedPref.UserIDNow= userID; has been executed , and also remove RunOnUiThread method ,you don't need to wrap code into it unless UI elements gets changed .
Use default SharedPreferences ,change preference as
private static ISharedPreferences preference = PreferenceManager.GetDefaultSharedPreferences(Application.Context);
Use Commit instead of Apply method on ISharedPreferencesEditor,Apply is asynchronous method which means if you read value too early ,you would get default value at that time .

Firebase data - error converting value

I have posted question regarding firebase two days ago:
Android Firebase - add authenticated user into database
I got help that I needed and that solved first problem. But now I have a new problem. I was googling for quite some time, there are some posts about this issue but nothing solved my problem. I din't want to spam the previous question so I posted a new one.
When I try reading inserted data from the firebase database I get this error:
Newtonsoft.Json.JsonSerializationException: Error converting value
"test#user.com" to type 'carServiceApp.My_Classes.Account'. Path
'email', line 1, position 24.
Here is the code:
private async Task LoadData()
{
FirebaseUser users = FirebaseAuth.GetInstance(loginActivity.app).CurrentUser;
id = users.Uid;
var firebase = new FirebaseClient(loginActivity.FirebaseURL);
var items = await firebase.Child("users").Child(id).OnceAsync<Account>();
foreach (var item in items)
{
Account user = new Account();
user.uid = item.Object.uid;
user.name = item.Object.name;
user.lastName = item.Object.lastName;
user.phone = item.Object.phone;
user.email = item.Object.email;
userInput_ime.Text = user.name;
userInput_prezime.Text = user.lastName;
userInput_broj.Text = user.phone;
userInput_email.Text = user.email;
}
}
This is firebase data:
-users
-jwAP2dYNzJeiF3QlmEIEQoruUkO2
email: "test#user.com"
lastName: "user"
name: "test"
phone: "12421"
uid: "jwAP2dYNzJeiF3QlmEIEQoruUkO2"
Interesting thing is that when I try reading data with this:
var items = await firebase.Child("users").OnceAsync<Account>();
This works fine (I get last inserted user) . But when I add 'uid' node, then I get error. I was trying to solve this for quite some time but I just can't figure it out. I guess that there is no problem with the account class because it works in the case without uid node but doesn't work when another child() method is added.
Other information (Account class code and the way of storing that data into the database) you can see in the link at the top.
Note: I tried adding constructor in Account class but that doesn't help.

Ok, so I didn't exactly find a solution for this problem nor do I really understand why was this happening but I have found a workaround. I believe it's not ideal solution and that it does not fix existing problem. Or maybe it was problem with me not understanding firebase logic but here is what I came up with.
So, considering that it was all working fine if I didn't specify that uid node it was obvious there was some problem with class and data in firebase, matching problem I guess. Anyway, I decided to have that last uid node so I can have specific user selected and also to have the same data in firebase as it was in case where it was all working. So, this is how I have inserted data into firebase:
var item = firebase.Child("users").Child(id).PostAsync<Account>(user);
This created users node and child node. And PostAsync method created one more node with random key.
So when I tried reading with this:
var data = await firebase.Child("users").Child(id).OnceAsync<Account>();
It worked without problem. Now firebase data looks like this:
users
JPKdQbwcXbhBatZ2ihBNLRauhV83
-LCXyLpvdfQ448KOPKUp
email: "spider#man.com"
lastName: "man"
name: "spider"
phone: "14412"
uid: "JPKdQbwcXbhBatZ2ihBNLRauhV83"
There is a bit of redundancy, I basically have two ID's, but I don't understand how to create my class so I can get that data any other way so I made it this way. It works fine.
If anyone has better solution, I will gladly change it. Cheers

This was suppose to be a comment, but this is just suppose to be an addition for anyone that needs help with this issue.
I know that this answer has been out there for a while but this still seems to be a running structural quirk with Firebase and the usage of their rules. I ran into this issue with a complex structure that looked kind of like this
-Orders
-9876trfghji (User ID)
-0
BusnID: "ty890oihg"
Name: "Some Name"
AddOns: Object
ItemData: Object(containing other objects)
UserID: "9876trfghji"
Note: In this case as well as the case with cordas, you will see that both of the final objects has a UserID or uid.
I also was running into the issue of class de-serialization of the object without having the actual User ID in the objects data when it was being sent back to the device.
The reason that you have a “redundant” usage of the user id is for a security measure with the Firebase rules. The first UserID with the structure above you are able to control the access to the information based off of the users id without having to have an extra validation clause in the rules. Currently as of this post the the rule below would protect the data based on the User ID.
“Orders” : {
"$uid":{
".read":"auth != null",
".write":"auth.uid == $uid"
}
}
this allows the user with only the authorized user id to write content but anyone that has valid credentials can view the data.
The second User ID has to be placed in the object because without it you would not be able to do a standard cast to the object because your object would not have all of the data it would need to create the object. Regardless of if you are using a package like GoogleGson or Newtonsoft.Json the object still isn't full.
There is how ever a work around for this problem besides re-entering the User ID into the object. With the object that I have above I decided to just re-enter the User ID in my personal code to save the time and hassle of manual creation.
Using the Firebase.Database NuGet package you can manually create the object. Here is an example of the object in cordas problem
public static void GetUser_Firebase(User user, FirebaseApp app)
{
FirebaseDatabase database = FirebaseDatabase.GetInstance(app);
DatabaseReference reference = database.GetReference($"/users/{user.UserID}");
//"Using for getting firebase information", $"/users/{user.UserID}"
reference.AddListenerForSingleValueEvent(new UserInfo_DataValue());
}
class UserInfo_DataValue : Java.Lang.Object, IValueEventListener
{
private string ID;
public UserInfo_DataValue(string uid)
{
this.ID = uid;
}
public void OnCancelled(DatabaseError error)
{
//"Failed To Get User Information For User "
}
public void OnDataChange(DataSnapshot snapshot)
{
Dictionary<string, string> Map = new Dictionary<string, string>();
var items = snapshot.Children?.ToEnumerable<DataSnapshot>(); // using Linq
foreach(DataSnapshot item in items)
{
try
{
Map.Add(item.Key, item.Value.ToString()); // item.value is a Java.Lang.Object
}
catch(Exception ex)
{
//"EXCEPTION WITH DICTIONARY MAP"
}
}
User toReturn = new User();
toReturn.UserID this.ID;
foreach (var item in Map)
{
switch (item.Key)
{
case "email":
toReturn.email = item.Value;
break;
case "lastName":
toReturn.lastName = item.Value;
break;
case "name":
toReturn.name = item.Value;
break;
case "phone":
toReturn.phone = item.Value;
break;
}
}
}
}
Update
There is something that I would like to mention that I left out when I was writing this and that is the usage of Firebase.Database NuGet package with the Gson NuGet package and the Newtonsoft.Json Library
If you decide to use the FIrebase.Database library just know that you will be working very close with the Java.Lang and the Java.Util libraries. Objects like Java.Lang.Object can be very difficult and time consuming to write the code needed to de-serialize the data, but don't fear Gson is here!
The Gson package if you allow it can take a large load of work off of your hands for class de-serialization if you allow it. Gson is a library that will allow you to do Java.Lang.Obj to json string de-serialization. I know it seems weird, hand it an object get back a string sounds counter intuitive I know but just bear with me.
Here is an example of how to us the Gson Library with the object in cordas problem.
public static void Get_User(User user, FirebaseApp app)
{
FirebaseDatabase database = FirebaseDatabase.GetInstance(app);
DatabaseReference reference = database.GetReference($"Users/{user.UserID}");
reference.AddListenerForSingleValueEvent(new User_DataValue(user, app));
//$"Trying to make call for user orders Users/{user.UserID}");
}
class User_DataValue : Java.Lang.Object, IValueEventListener
{
private User User;
private FirebaseApp app;
public UserOrderID_Init_DataValue(User user, FirebaseApp app)
{
this.User = user;
this.app = app;
}
public void OnCancelled(DatabaseError error)
{
//$"Failed To Get User Orders {error.Message}");
}
public void OnDataChange(DataSnapshot snapshot)
{
//"Data received for user orders");
var gson = new GsonBuilder().SetPrettyPrinting().Create();
var json = gson.ToJson(snapshot.Value); // Gson extention method obj -> string
Formatted_Output("Data received for user order json ", json);
User user = JsonConvert.DeserializeObject<User>(json); //Newtonsoft.Json extention method string -> object
//now the user is a fully populated object with very little work
}
For anyone that might run into this in the future I hope that this helps

Not able to retrieve OriginalValues in Entity Framework 5

I am writing a asp.net mvc4 app and I am using entity framework 5. Each of my entities have fields like EnteredBy, EnteredOn, LastModifiedBy and LastModifiedOn.
I am trying to auto-save them by using the SavingChanges event. The code below has been put together from numerous blogs, SO answeres etc.
public partial class myEntities : DbContext
{
public myEntities()
{
var ctx = ((IObjectContextAdapter)this).ObjectContext;
ctx.SavingChanges += new EventHandler(context_SavingChanges);
}
private void context_SavingChanges(object sender, EventArgs e)
{
ChangeTracker.DetectChanges();
foreach (ObjectStateEntry entry in
((ObjectContext)sender).ObjectStateManager
.GetObjectStateEntries
(EntityState.Added | EntityState.Modified))
{
if (!entry.IsRelationship)
{
CurrentValueRecord entryValues = entry.CurrentValues;
if (entryValues.GetOrdinal("LastModifiedBy") > 0)
{
HttpContext currContext = HttpContext.Current;
string userName = "";
DateTime now = DateTime.Now;
if (currContext.User.Identity.IsAuthenticated)
{
if (currContext.Session["userId"] != null)
{
userName = (string)currContext.Session["userName"];
}
else
{
userName = currContext.User.Identity.Name;
}
}
entryValues.SetString(
entryValues.GetOrdinal("LastModifiedBy"), userName);
entryValues.SetDateTime(
entryValues.GetOrdinal("LastModifiedOn"), now);
if (entry.State == EntityState.Added)
{
entryValues.SetString(
entryValues.GetOrdinal("EnteredBy"), userName);
entryValues.SetDateTime(
entryValues.GetOrdinal("EnteredOn"), now);
}
else
{
string enteredBy =
entry.OriginalValues.GetString(entryValues.GetOrdinal("EnteredBy"));
DateTime enteredOn =
entry.OriginalValues.GetDateTime(entryValues.GetOrdinal("EnteredOn"));
entryValues.SetString(
entryValues.GetOrdinal("EnteredBy"),enteredBy);
entryValues.SetDateTime(
entryValues.GetOrdinal("EnteredOn"), enteredOn);
}
}
}
}
}
}
My problem is that entry.OriginalValues.GetString(entryValues.GetOrdinal("EnteredBy")) and entry.OriginalValues.GetDateTime(entryValues.GetOrdinal("EnteredOn")) are not returning the original values but rather the current values which is null. I tested with other fields in the entity and they are returning the current value which were entered in the html form.
How do I get the original value here?

I think the problem may be that you are using the instance provided by the model binder as the input to your controller method, so EF does not know anything about that entity and its original state. Your code may look like this:
public Review Update(Review review)
{
_db.Entry(review).State = EntityState.Modified;
_db.SaveChanges();
return review;
}
In that case, EF knows nothing about the Review instance that is being saved. It is trusting you and setting it as modified, so it will save all of its properties to the database, but it does not know the original state\values of that entity.
Check the section named Entity States and the Attach and SaveChanges Methods of this tutorial. You can also check the first part of this article, that shows how EF does not know about the original values and will update all properties in the database.
As EF will need to know about the original properties, you may first load your entity from the database and then update its properties with the values received in the controller. Something like this:
public Review Update(Review review)
{
var reviewToSave = _db.Reviews.SingleOrDefault(r => r.Id == review.Id);
//Copy properties from entity received in controller to entity retrieved from the database
reviewToSave.Property1 = review.Property1;
reviewToSave.Property2 = review.Property2;
...
_db.SaveChanges();
return review;
}
This has the advantage that only modified properties will be send and updated in the database and that your views and view models don't need to expose every field in your business objects, only those that can be updated by the users. (Opening the door for having different classes for viewModels and models\business objects). The obvious disadvantage is that you will incur an additional hit to the database.
Another option mentioned in the tutorial I referenced above is for you to save the original values somehow (hidden fields, session, etc) and on save use the original values to attach the entity to the database context as unmodified. Then update that entity with the edited fields. However I would not recommend this approach unless you really need to avoid that additional database hit.
Hope that helps!

I was running into a similar problem when trying to audit log the Modified values of an Entity.
It turns out during the post back the ModelBinder doesn't have access to the original values so the Model received is lacking the correct information. I fixed my problem by using this function which clones the current values, relods the object, and then reset the current values.
void SetCorrectOriginalValues(DbEntityEntry Modified)
{
var values = Modified.CurrentValues.Clone();
Modified.Reload();
Modified.CurrentValues.SetValues(values);
Modified.State = EntityState.Modified;
}
You can gain access to the DbEntityEntry though the change tracker, or the entry function from your context.

Update custom user profile fields with SimpleMembershipProvider?

I added a custom field to the UserProfile table named ClassOfYear and I'm able to get the data into the profile during registration like this:
var confirmationToken = WebSecurity.CreateUserAndAccount(model.UserName,
model.Password,
propertyValues: new { ClassOfYear = model.ClassOfYear },
requireConfirmationToken: true);
However, now I want to be able to update the profile when I manage it but I can't seem to find a method to do so. Do I need to simply update the UserProfile table myself? If not, what is the appropriate way of doing this?
FYI, I'm using Dapper as my data access layer, just in case it matters. But, like stated, I can just update the UserProfile table via Dapper if that's what I'm supposed to do, I just figured that the WebSecurity class, or something similar, had a way already since the custom user profile fields are integrated with the CreateUserAndAccount method.
Thanks all!

There is nothing in the SimpleMembershipProvider code that does anything with additional fields except upon create.
Simply query the values yourself from your ORM.
You can use the WebSecurity.GetUserId(User.Identity.Name) to get the user's id and then Dapper to query the UserProfile table.

Just in case anyone facing the same problem. After fighting a lot with the SimpleMembership I got a solution that populates both the webpages_Membership and my custom Users table. For clarification follow my code:
public ActionResult Register(RegisterModel model)
{
if (ModelState.IsValid)
{
TUsuario userDTO= new TUSer()
{
Name = model.Name,
Login = model.Login,
Pass = model.Pass.ToString(CultureInfo.InvariantCulture),
Active = true,
IdCompany = model.IdCompany,
IdUserGroup = model.IdUserGroup,
};
try
{
WebSecurity.CreateUserAndAccount(model.Login, model.Pass, new { IdUser = new UserDAL().Seq.NextVal(), Name = userDTO.Name, Login = userDTO.Login, Active = userDTO.Active, Pass = userDTO.Pass, IdCompany = userDTO.IdCompany, IdUserGroup = userDTO.IdUserGroup });
WebSecurity.Login(model.Login, model.Pass);
After cursing the framework a lot, that gave me a bliss of fresh air :)
PS.: The users table is specified in the global.asax file using the WebSecurity.InitializeDatabaseConnection functon.

In MVC Edit Action {HTTP POST} Using UpdateModel vs Request.Form Collection

I am working through sample MVC Nerdinner tutorial and using it on the AdventureWorks database. I have created an Edit action in the CategoryController to edit Product Category in AdventureWorks. The only updateable field in this table is the Name (the other fields - ID, RowGUID and UpdateDate are autogenerated). So my edit form View has only 1 field for the Name (of Product Category). My "Save" action for the edit is below: -
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult Edit(int id, FormCollection collection){
ProductCategory p = awRepository.GetProductCategory(id);
try
{
//UpdateModel(p);
p.Name = Request.Form["Name"];
awRepository.Save();
return RedirectToAction("Details", new { id = p.ProductCategoryID });
}
catch
{
foreach (var err in p.GetRuleViolations())
{
ModelState.AddModelError(err.PropertyName, err.ErrorMessage);
}
return View(p);
}
}
If I use the code as above, everything works as long as the Name I enter is valid (thus there is no exception). If I introduce an error (which is raised by GetRuleViolations if the Name is blank or for testing purposes is a particular "Test" string) I get a NullReferenceException (Object reference not set to an instance of an object) on this line in the View (Category/Edit.aspx) when the Edit View is redrawn (to show the user the error and allow him to correct)
<%= Html.TextBox("Name") %>
If I update my ProductCategory using UpdateModel(p) instead of using the Request.Form variable, everything works fine; Valid data is saved and invalid data redraws the view showing the error message.
My question is: what is the difference between UpdateModel and manual updating my variable by reading the values from Request.Form collection? The Nerdinner tutorial seems to suggest that both are equivalent. So I am surprised that one works smoothly and the other raises an exception.

Sounds like this:
http://forums.asp.net/p/1396019/3006051.aspx
So, for every error you add with
ModelState.AddModelError() and call
the View again, MVC Framework will try
to find an AttemptedValue for every
error it finds. Because you didn't add
them, MVC will throw an exception.
Normally you don't need to add these
values: AttemptedValues are
automaticaly populated when you use
DefaultBinding (by calling
UpdateModel() or by passing the object
to bind as an Action Method paramter:
public ActionResult
Create(FormCollection Form,
YourObjectType yourObject).
Looks like the following is done automatically by UpdateModel, but not done manually by yourself?
if (Form["Name"].Trim().Length == 0)
{
ModelState.AddModelError("Name", "Name is required");
//You missed off SetModelValue?
ModelState.SetModelValue("Name", Form.ToValueProvider()["Name"]);
}