Posting JSON Data to ASP NET MVC

Question

Im trying to get a list of line items to a webpage using JSON  which will then be manipulated and sent back to the server by ajax request using the same JSON structure that arrived  except having had a field values changed     Receiving data from the server is easy  manipulation even easier  but sending that JSON data back to the server for saving    suicide time  PLEASE can someone help   Javascript  var lineitems      get data from server   ajax       url    Controller GetData        success  function data           lineitems   data                post data to server   ajax       url    Controller SaveData        data    incoming  lineitems         C  - Objects  public class LineItem      public string reference      public int quantity      public decimal amount      C  - Controller  public JsonResult GetData         IEnumerable lt LineItem gt  lineItems            a whole bunch of line items     return Json lineItems      public JsonResult SaveData IEnumerable lt LineItem gt  incoming       foreach LineItem item in incoming              save some stuff           return Json new   success   true  message    Some message          The data arrives at the server as serialized post data  The automated model binder tries to bind IEnumerable lt LineItem gt  incoming and surprisingly gets the resulting IEnumerable has the correct number of LineItems - it just doesnt populate them with data   SOLUTION  Using answers from a number of sources  primarily djch on another stackoverflow post and BeRecursive below  I solved my problem using two main methods   Server Side   The deserialiser below requires reference to System Runtime Serialization and using System Runtime Serialization Json  private T Deserialise lt T gt  string json        using  var ms   new MemoryStream Encoding Unicode GetBytes json                  var serialiser   new DataContractJsonSerializer typeof T            return  T serialiser ReadObject ms            public void Action int id  string items       IEnumerable lt LineItem gt  lineitems   Deserialise lt IEnumerable lt LineItem gt  gt  items          do whatever needs to be done - create  update  delete etc      Client Side  It uses json org s stringify method  available in this dependecy https   github com douglascrockford JSON-js blob master json2 js  which is 2 5kb when minified     ajax       type   POST       url    Controller Action       data     items   JSON stringify lineItems    id   documentId

User · Answer

The simplest way of doing this  I urge you to read this blog post that directly addresses your problem   Using custom model binders isn t really wise as Phil Haack pointed out  his blog post is linked in the upper blog post as well    Basically you have three options    Write a JsonValueProviderFactory and use a client side library like json2 js to communicate wit JSON directly  Write a JQueryValueProviderFactory that understands the jQuery JSON object transformation that happens in   ajax or Use the very simple and quick jQuery plugin outlined in the blog post  that prepares any JSON object  even arrays that will be bound to IList lt T gt  and dates that will correctly parse on the server side as DateTime instances  that will be understood by Asp net MVC default model binder    Of all three  the last one is the simplest and doesn t interfere with Asp net MVC inner workings thus lowering possible bug surface  Using this technique outlined in the blog post will correctly data bind your strong type action parameters and validate them as well  So it is basically a win win situation

User · Answer

BeRecursive s answer is the one I used  so that we could standardize on Json Net  we have MVC5 and WebApi 5 -- WebApi 5 already uses Json Net   but I found an issue  When you have parameters in your route to which you re POSTing  MVC tries to call the model binder for the URI values  and this code will attempt to bind the posted JSON to those values   Example    HttpPost   Route  Customer  customerId int  Vehicle  vehicleId int  Policy Create   public async Task lt JsonNetResult gt  Create int customerId  int vehicleId  PolicyRequest policyRequest    The BindModel function gets called three times  bombing on the first  as it tries to bind the JSON to customerId with the error  Error reading integer  Unexpected token  StartObject  Path     line 1  position 1   I added this block of code to the top of BindModel   if  bindingContext ValueProvider GetValue bindingContext ModelName     null        return base BindModel controllerContext  bindingContext       The ValueProvider  fortunately  has route values figured out by the time it gets to this method

User · Answer

I solved using a  manual  deserialization  I ll explain in code  public ActionResult MyMethod  System Web Http FromBody  MyModel model     if  module Fields    null  amp  amp   string IsNullOrEmpty Request Form  fields           model Fields   JsonConvert DeserializeObject lt MyFieldModel   gt  Request Form  fields               more code

User · Answer

I see everyone here  took the long route    As long as you are using MVC  I strongly recommend you to use the easiest method over all which is Newtonsoft JSON    Also If you dont wanna use libraries check the answer links below  I took a good research time for this to solve the issue for my self and these are the solutions I found   First implement the Newtonsoft Json   using Newtonsoft Json    Prepare your Ajax request     ajax       dataType   json       contentType   application json                   type   POST       url    Controller Action       data     items   JSON stringify lineItems    id   documentId         Then go for your result class   public ActionResult SaveData string incoming  int documentId          DeSerialize into your Model as your Model Array     LineItem   jsr   JsonConvert DeserializeObject lt LineItem   gt  Temp       foreach LineItem item in jsr              save some stuff           return Json new   success   true  message    Some message          See the trick up there  Instead of using JsonResult I used regular ActionResult with a string which includes json string  Then deserialized into my Model so I can use this in any action method I have   Plus sides of this method is     Easier to pass between actions  Lesser and more clear usage of code  No need to change your model  Simple implementation with JSON stringify Model  Passing only string   Down sides of this method is     Passing only string Deserialization process   Also check these questions and answers which are really helpfull    https   stackoverflow com a 45682516 861019  another method     https   stackoverflow com a 31656160 861019  and another method    https   stackoverflow com a 50787450 861019

User · Answer

I solved this problem following vestigal s tips here   Can I set an unlimited length for maxJsonLength in web config   When I needed to post a large json to an action in a controller  I would get the famous  Error during deserialization using the JSON JavaScriptSerializer  The length of the string exceeds the value set on the maxJsonLength property  r nParameter name  input value provider    What I did is create a new ValueProviderFactory  LargeJsonValueProviderFactory  and set the  MaxJsonLength   Int32 MaxValue in the GetDeserializedObject method  public sealed class LargeJsonValueProviderFactory   ValueProviderFactory       private static void AddToBackingStore LargeJsonValueProviderFactory EntryLimitedDictionary backingStore  string prefix  object value                IDictionary lt string  object gt  dictionary   value as IDictionary lt string  object gt           if  dictionary    null                        foreach  KeyValuePair lt string  object gt  keyValuePair in  IEnumerable lt KeyValuePair lt string  object gt  gt   dictionary                  LargeJsonValueProviderFactory AddToBackingStore backingStore  LargeJsonValueProviderFactory MakePropertyKey prefix  keyValuePair Key   keyValuePair Value                     else                       IList list   value as IList              if  list    null                                for  int index   0  index  lt  list Count    index                      LargeJsonValueProviderFactory AddToBackingStore backingStore  LargeJsonValueProviderFactory MakeArrayKey prefix  index   list index                              else                 backingStore Add prefix  value                        private static object GetDeserializedObject ControllerContext controllerContext                if   controllerContext HttpContext Request ContentType StartsWith  application json   StringComparison OrdinalIgnoreCase               return  object  null          string end   new StreamReader controllerContext HttpContext Request InputStream  ReadToEnd            if  string IsNullOrEmpty end               return  object  null           var serializer   new JavaScriptSerializer  MaxJsonLength   Int32 MaxValue            return serializer DeserializeObject end                   lt summary gt Returns a JSON value-provider object for the specified controller context  lt  summary gt           lt returns gt A JSON value-provider object for the specified controller context  lt  returns gt           lt param name  controllerContext  gt The controller context  lt  param gt      public override IValueProvider GetValueProvider ControllerContext controllerContext                if  controllerContext    null              throw new ArgumentNullException  controllerContext            object deserializedObject   LargeJsonValueProviderFactory GetDeserializedObject controllerContext           if  deserializedObject    null              return  IValueProvider  null          Dictionary lt string  object gt  dictionary   new Dictionary lt string  object gt   IEqualityComparer lt string gt   StringComparer OrdinalIgnoreCase           LargeJsonValueProviderFactory AddToBackingStore new LargeJsonValueProviderFactory EntryLimitedDictionary  IDictionary lt string  object gt   dictionary   string Empty  deserializedObject           return  IValueProvider  new DictionaryValueProvider lt object gt   IDictionary lt string  object gt   dictionary  CultureInfo CurrentCulture              private static string MakeArrayKey string prefix  int index                return prefix         index ToString  IFormatProvider  CultureInfo InvariantCulture                    private static string MakePropertyKey string prefix  string propertyName                if   string IsNullOrEmpty prefix               return prefix         propertyName          return propertyName             private class EntryLimitedDictionary               private static int  maximumDepth   LargeJsonValueProviderFactory EntryLimitedDictionary GetMaximumDepth            private readonly IDictionary lt string  object gt   innerDictionary          private int  itemCount           public EntryLimitedDictionary IDictionary lt string  object gt  innerDictionary                        this  innerDictionary   innerDictionary                     public void Add string key  object value                        if    this  itemCount  gt  LargeJsonValueProviderFactory EntryLimitedDictionary  maximumDepth                  throw new InvalidOperationException  JsonValueProviderFactory RequestTooLarge                this  innerDictionary Add key  value                      private static int GetMaximumDepth                         NameValueCollection appSettings   ConfigurationManager AppSettings              if  appSettings    null                                string   values   appSettings GetValues  aspnet MaxJsonDeserializerMembers                    int result                  if  values    null  amp  amp  values Length  gt  0  amp  amp  int TryParse values 0   out result                       return result                            return 1000                      Then  in the Application Start method from Global asax cs  replace the ValueProviderFactory with the new one   protected void Application Start                                Add LargeJsonValueProviderFactory         ValueProviderFactory jsonFactory   null          foreach  var factory in ValueProviderFactories Factories                        if  factory GetType   FullName     System Web Mvc JsonValueProviderFactory                                 jsonFactory   factory                  break                                   if  jsonFactory    null                        ValueProviderFactories Factories Remove jsonFactory                      var largeJsonValueProviderFactory   new LargeJsonValueProviderFactory            ValueProviderFactories Factories Add largeJsonValueProviderFactory

User · Answer

You can try these  1  stringify your JSON Object before calling the server action via ajax 2  deserialize the string in the action then use the data as a dictionary   Javascript sample below  sending the JSON Object    ajax              type   POST          url   TheAction          data     data   JSON stringify theJSONObject             Action  C   sample below   HttpPost  public JsonResult TheAction string data            string  jsonObject   data Replace       string Empty          var serializer   new System Web Script Serialization JavaScriptSerializer                       Dictionary lt string  string gt  jsonObject   serializer Deserialize lt Dictionary lt string  string gt  gt   jsonObject             return Json new object status   true

User · Answer

Take a look at Phil Haack s post on model binding JSON data  The problem is that the default model binder doesn t serialize JSON properly  You need some sort of ValueProvider OR you could write a custom model binder   using System IO  using System Web Script Serialization   public class JsonModelBinder   DefaultModelBinder           public override object BindModel ControllerContext controllerContext  ModelBindingContext bindingContext                if  IsJSONRequest controllerContext                     return base BindModel controllerContext  bindingContext                                 Get the JSON data that s been posted             var request   controllerContext HttpContext Request                in some setups there is something that already reads the input stream if content type    application json   so seek to the begining             request InputStream Seek 0  SeekOrigin Begin               var jsonStringData   new StreamReader request InputStream  ReadToEnd                    Use the built-in serializer to do the work for us             return new JavaScriptSerializer                    Deserialize jsonStringData  bindingContext ModelMetadata ModelType                   -- REQUIRES  NET4                If you want to use the  NET4 version of this  change the target framework and uncomment the line below                and comment out the above return statement               return new JavaScriptSerializer   Deserialize jsonStringData  bindingContext ModelMetadata ModelType                      private static bool IsJSONRequest ControllerContext controllerContext                var contentType   controllerContext HttpContext Request ContentType              return contentType Contains  application json                     public static class JavaScriptSerializerExt           public static object Deserialize this JavaScriptSerializer serializer  string input  Type objType                var deserializerMethod   serializer GetType   GetMethod  Deserialize   BindingFlags NonPublic   BindingFlags Static                   internal static method to do the work for us               Deserialize this  input  null  this RecursionLimit                return deserializerMethod Invoke serializer                  new object     serializer  input  objType  serializer RecursionLimit                       And tell MVC to use it in your Global asax file   ModelBinders Binders DefaultBinder   new JsonModelBinder      Also  this code makes use of the content type    application json  so make sure you set that in jquery like so     ajax       dataType   json       contentType   application json                   type   POST       url    Controller Action       data     items   JSON stringify lineItems    id   documentId

User · Answer

In MVC3 they ve added this   But whats even more nice is that since MVC source code is open you can grab the ValueProvider and use it yourself in your own code  if youre not on MVC3 yet    You will end up with something like this  ValueProviderFactories Factories Add new JsonValueProviderFactory

User · Answer

If you ve got ther JSON data coming in as a string  e g      id  1  name   Charles     id  8  name   John     id  13  name   Sally       Then I d use JSON net and use Linq to JSON to get the values out     using System  using System Collections Generic  using System Linq  using System Web  using System Web UI  using System Web UI WebControls  using Newtonsoft Json  using Newtonsoft Json Linq   public partial class  Default   System Web UI Page   protected void Page Load object sender  EventArgs e         if  Request  items      null                var items   Request  items   ToString       Get the JSON string         JArray o   JArray Parse items      It is an array so parse into a JArray         var a   o SelectToken   0  name   ToString       Get the name value of the 1st object in the array            a     Charles

[c#] Posting JSON Data to ASP.NET MVC

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