Can I set an unlimited length for maxJsonLength in web config

Question

I am using the autocomplete feature of jQuery  When I try to retrieve the list of more then 17000 records  each won t have more than 10 char length   it s exceeding the length and throws the error      Exception information         Exception type  InvalidOperationException        Exception message  Error during serialization or deserialization using the JSON JavaScriptSerializer  The length of the string exceeds the value set on the maxJsonLength property    Can I set an unlimited length for maxJsonLength in web config  If not  what is the maximum length I can set

User · Answer

You can set it in the config as others have said  or you can set in on an individual instance of the serializer like   var js   new JavaScriptSerializer     MaxJsonLength   int MaxValue

User · Answer

How about some attribute magic    AttributeUsage AttributeTargets Class   AttributeTargets Method  Inherited   true  AllowMultiple   false   public class MaxJsonSizeAttribute   ActionFilterAttribute          Default  10 MB worth of one byte chars     private int maxLength   10   1024   1024       public int MaxLength               set                       if  value  lt  0  throw new ArgumentOutOfRangeException  value    Value must be at least 0                  maxLength   value                    get   return maxLength               public override void OnActionExecuted ActionExecutedContext filterContext                JsonResult json   filterContext Result as JsonResult          if  json    null                        if  maxLength    0                                json MaxJsonLength   int MaxValue                            else                               json MaxJsonLength   maxLength                                    Then you could either apply it globally using the global filter configuration or controller action-wise

User · Answer

The question really is whether you really need to return 17k records  How are you planning to handle all the data in the browser  The users are not going to scroll through 17000 rows anyway   A better approach is to retrieve only a  top few  records and load more as required

User · Answer

Fix for ASP NET MVC  if you want to fix it only for particular action that is causing the problem then change this code  public JsonResult GetBigJson         var someBigObject   GetBigObject        return Json someBigObject      to this  public JsonResult GetBigJson         var someBigObject   GetBigObject        return new JsonResult                 Data   someBigObject          JsonRequestBehavior   JsonRequestBehavior DenyGet          MaxJsonLength   int MaxValue           And the functionality should be same  you can just return bigger JSON as response   Explanation based on ASP NET MVC source code  you can check what Controller Json method does in ASP NET MVC source code protected internal JsonResult Json object data        return Json data  null    contentType     null    contentEncoding     JsonRequestBehavior DenyGet      It is calling other Controller Json method  protected internal virtual JsonResult Json object data  string contentType  Encoding contentEncoding  JsonRequestBehavior behavior        return new JsonResult               Data   data          ContentType   contentType          ContentEncoding   contentEncoding          JsonRequestBehavior   behavior           where passed contentType and contentEncoding object are null  So basically calling return Json object  in controller is equivalent to calling return new JsonResult   Data   object  JsonRequestBehavior   sonRequestBehavior DenyGet    You can use second form and parameterize JsonResult  So what happens when you set MaxJsonLength property  by default it s null   It s passed down to JavaScriptSerializer MaxJsonLength property and then JavaScriptSerializer Serialize method is called   JavaScriptSerializer serializer   new JavaScriptSerializer    if  MaxJsonLength HasValue        serializer MaxJsonLength   MaxJsonLength Value     if  RecursionLimit HasValue        serializer RecursionLimit   RecursionLimit Value     response Write serializer Serialize Data     And when you don t set MaxJsonLenght property of serializer then it takes default value which is just 2MB

User · Answer

Alternative ASP NET MVC 5 Fix    Mine is similar to MFCs answer above with a few small changes   I wasn t ready to change to Json NET just yet and in my case the error was occurring during the request  Best approach in my scenario was modifying the actual JsonValueProviderFactory which applies the fix to the global project and can be done by editing the global cs file as such   JsonValueProviderConfig Config ValueProviderFactories Factories     add a web config entry    lt add key  aspnet MaxJsonLength  value  20971520    gt    and then create the two following classes  public class JsonValueProviderConfig       public static void Config ValueProviderFactoryCollection factories                var jsonProviderFactory   factories OfType lt JsonValueProviderFactory gt    Single            factories Remove jsonProviderFactory           factories Add new CustomJsonValueProviderFactory               This is basically an exact copy of the default implementation found in System Web Mvc but with the addition of a configurable web config appsetting value aspnet MaxJsonLength   public class CustomJsonValueProviderFactory   ValueProviderFactory             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   CustomJsonValueProviderFactory GetDeserializedObject controllerContext           if  deserializedObject    null              return null           Dictionary lt string  object gt  strs   new Dictionary lt string  object gt  StringComparer OrdinalIgnoreCase           CustomJsonValueProviderFactory AddToBackingStore new CustomJsonValueProviderFactory EntryLimitedDictionary strs   string Empty  deserializedObject            return new DictionaryValueProvider lt object gt  strs  CultureInfo CurrentCulture              private static object GetDeserializedObject ControllerContext controllerContext                if   controllerContext HttpContext Request ContentType StartsWith  application json   StringComparison OrdinalIgnoreCase               return null           string fullStreamString    new StreamReader controllerContext HttpContext Request InputStream   ReadToEnd            if  string IsNullOrEmpty fullStreamString               return null           var serializer   new JavaScriptSerializer                         MaxJsonLength   CustomJsonValueProviderFactory GetMaxJsonLength                      return serializer DeserializeObject fullStreamString              private static void AddToBackingStore EntryLimitedDictionary backingStore  string prefix  object value                IDictionary lt string  object gt  strs   value as IDictionary lt string  object gt           if  strs    null                        foreach  KeyValuePair lt string  object gt  keyValuePair in strs                  CustomJsonValueProviderFactory AddToBackingStore backingStore  CustomJsonValueProviderFactory MakePropertyKey prefix  keyValuePair Key   keyValuePair Value                return                     IList lists   value as IList          if  lists    null                        backingStore Add prefix  value               return                     for  int i   0  i  lt  lists Count  i                          CustomJsonValueProviderFactory AddToBackingStore backingStore  CustomJsonValueProviderFactory MakeArrayKey prefix  i   lists i                         private class EntryLimitedDictionary               private static int  maximumDepth           private readonly IDictionary lt string  object gt   innerDictionary           private int  itemCount           static EntryLimitedDictionary                          maximumDepth   CustomJsonValueProviderFactory GetMaximumDepth                       public EntryLimitedDictionary IDictionary lt string  object gt  innerDictionary                        this  innerDictionary   innerDictionary                     public void Add string key  object value                        int num   this  itemCount   1              this  itemCount   num              if  num  gt   maximumDepth                                throw new InvalidOperationException  The length of the string exceeds the value set on the maxJsonLength property                               this  innerDictionary Add key  value                        private static string MakeArrayKey string prefix  int index                return string Concat prefix       index ToString CultureInfo InvariantCulture                    private static string MakePropertyKey string prefix  string propertyName                if  string IsNullOrEmpty prefix                         return propertyName                    return string Concat prefix       propertyName              private static int GetMaximumDepth                 int num          NameValueCollection appSettings   ConfigurationManager AppSettings          if  appSettings    null                        string   values   appSettings GetValues  aspnet MaxJsonDeserializerMembers                if  values    null  amp  amp  values Length    0  amp  amp  int TryParse values 0   out num                                 return num                                  return 1000             private static int GetMaxJsonLength                 int num          NameValueCollection appSettings   ConfigurationManager AppSettings          if  appSettings    null                        string   values   appSettings GetValues  aspnet MaxJsonLength                if  values    null  amp  amp  values Length    0  amp  amp  int TryParse values 0   out num                                 return num                                  return 1000

User · Answer

You can configure the max length for json requests in your web config file    lt configuration gt       lt system web extensions gt           lt scripting gt               lt webServices gt                   lt jsonSerialization maxJsonLength        gt                   lt  jsonSerialization gt               lt  webServices gt           lt  scripting gt       lt  system web extensions gt   lt  configuration gt    The default value for maxJsonLength is 102400  For more details  see this MSDN page  http   msdn microsoft com en-us library bb763183 aspx

User · Answer

I suggest setting it to Int32 MaxValue   JavaScriptSerializer serializer   new JavaScriptSerializer    serializer MaxJsonLength   Int32 MaxValue

User · Answer

NOTE  this answer applies only to Web services  if you are returning JSON from a Controller method  make sure you read this SO answer below as well  https   stackoverflow com a 7207539 1246870    The MaxJsonLength property cannot be unlimited  is an integer property that defaults to 102400  100k    You can set the MaxJsonLength property on your web config    lt configuration gt       lt system web extensions gt          lt scripting gt              lt webServices gt                  lt jsonSerialization maxJsonLength  50000000   gt              lt  webServices gt          lt  scripting gt      lt  system web extensions gt   lt  configuration gt

User · Answer

You do not need to do with web config You can use short property during catch value of the passing list For example declare a model like  public class BookModel               public decimal id   get  set        1           public string BN   get  set       2 Book Name          public string BC   get  set       3 Bar Code Number          public string BE   get  set       4 Edition Name          public string BAL   get  set       5 Academic Level          public string BCAT   get  set       6 Category     here i use short proporties like  BC  barcode BE book edition and so on

User · Answer

I fixed it     your Json data here string json object             JavaScriptSerializer jsJson   new JavaScriptSerializer    jsJson MaxJsonLength   2147483644  MyClass obj   jsJson Deserialize lt MyClass gt  json object     It works very well

User · Answer

JsonResult result   Json r    result MaxJsonLength   Int32 MaxValue   result JsonRequestBehavior   JsonRequestBehavior AllowGet   return result

User · Answer

Solution for WebForms UpdatePanel   Add a setting to Web config    lt configuration gt     lt appSettings gt       lt add key  aspnet UpdatePanelMaxScriptLength  value  2147483647    gt     lt  appSettings gt   lt  configuration gt    https   support microsoft com en-us kb 981884  ScriptRegistrationManager class contains following code      Serialize the attributes to JSON and write them out JavaScriptSerializer serializer   new JavaScriptSerializer        Dev10  877767 - Allow configurable UpdatePanel script block length    The default is JavaScriptSerializer DefaultMaxJsonLength if  AppSettings UpdatePanelMaxScriptLength  gt  0        serializer MaxJsonLength   AppSettings UpdatePanelMaxScriptLength       string attrText   serializer Serialize attrs

User · Answer

Simply set MaxJsonLength proprty in MVC s Action method  JsonResult json  Json classObject  JsonRequestBehavior AllowGet   json MaxJsonLength   int MaxValue  return json

User · Answer

I was having this problem in ASP NET Web Forms  It was completely ignoring the web config file  settings so I did this           JavaScriptSerializer serializer   new JavaScriptSerializer             serializer MaxJsonLength   Int32 MaxValue            return serializer Serialize response     Of course overall this is terrible practice  If you are sending this much data in a web service call you should look at a different approach

User · Answer

If you are getting this error from the MiniProfiler in MVC then you can increase the value by setting the property MiniProfiler Settings MaxJsonResponseSize to the desired value  By default  this tool seems to ignore the value set in config   MiniProfiler Settings MaxJsonResponseSize   104857600    Courtesy mvc-mini-profiler

User · Answer

you can write this line into Controller  json MaxJsonLength   2147483644    you can also write this line into web config   lt configuration gt     lt system web extensions gt       lt scripting gt           lt webServices gt               lt jsonSerialization maxJsonLength  2147483647  gt               lt  jsonSerialization gt           lt  webServices gt       lt  scripting gt     lt  system web extensions gt        To be on the safe side  use both

User · Answer

if  after implementing the above addition into your web config  you get an    Unrecognized configuration section system web extensions     error then try adding this to your web config in the  lt ConfigSections gt  section                lt sectionGroup name  system web extensions  type  System Web Extensions  gt                 lt sectionGroup name  scripting  type  System Web Extensions  gt                       lt sectionGroup name  webServices  type  System Web Extensions  gt                             lt section name  jsonSerialization  type  System Web Extensions   gt                       lt  sectionGroup gt                 lt  sectionGroup gt           lt  sectionGroup gt

User · Answer

If you are using MVC 4  be sure to check out this answer as well   If you are still receiving the error   after setting the maxJsonLength property to its maximum value in web config and you know that your data s length is less than this value and you are not utilizing a web service method for the JavaScript serialization  your problem is is likely that   The value of the MaxJsonLength property applies only to the internal JavaScriptSerializer instance that is used by the asynchronous communication layer to invoke Web services methods   MSDN  ScriptingJsonSerializationSection MaxJsonLength Property   Basically  the  quot internal quot  JavaScriptSerializer respects the value of maxJsonLength when called from a web method  direct use of a JavaScriptSerializer  or use via an MVC action-method Controller  does not respect the maxJsonLength property  at least not from the systemWebExtensions scripting webServices jsonSerialization section of web config  In particular  the Controller Json   method does not respect the configuration setting  As a workaround  you can do the following within your Controller  or anywhere really   var serializer   new JavaScriptSerializer        For simplicity just use Int32 s max value     You could always read the value from the config section mentioned above  serializer MaxJsonLength   Int32 MaxValue   var resultData   new   Value    quot foo quot   Text    quot var quot     var result   new ContentResult      Content   serializer Serialize resultData       ContentType    quot application json quot     return result    This answer is my interpretation of this asp net forum answer

User · Answer

I solved the problem adding this code   String confString   HttpContext Current Request ApplicationPath ToString    Configuration conf   WebConfigurationManager OpenWebConfiguration confString   ScriptingJsonSerializationSection section    ScriptingJsonSerializationSection conf GetSection  system web extensions scripting webServices jsonSerialization    section MaxJsonLength   6553600  conf Save

User · Answer

if you are still getting error after web config setting like following    lt configuration gt       lt system web extensions gt          lt scripting gt              lt webServices gt                  lt jsonSerialization maxJsonLength  50000000   gt              lt  webServices gt          lt  scripting gt      lt  system web extensions gt   lt  configuration gt     I solved it by following      public ActionResult JsonResult getData              var jsonResult   Json superlargedata  JsonRequestBehavior AllowGet         jsonResult MaxJsonLength   int MaxValue        return jsonResult          I hope this should help

User · Answer

In MVC 4 you can do   protected override JsonResult Json object data  string contentType  System Text Encoding contentEncoding  JsonRequestBehavior behavior        return new JsonResult                 Data   data          ContentType   contentType          ContentEncoding   contentEncoding          JsonRequestBehavior   behavior          MaxJsonLength   Int32 MaxValue            in your controller   Addition   For anyone puzzled by the parameters you need to specify  a call could look like this   Json      new           field1   true          field2    value                  application json       Encoding UTF8      JsonRequestBehavior AllowGet

User · Answer

For those who are having issues with in MVC3 with JSON that s automatically being deserialized for a model binder and is too large  here is a solution    Copy the code for the JsonValueProviderFactory class from the MVC3 source code into a new class  Add a line to change the maximum JSON length before the object is deserialized  Replace the JsonValueProviderFactory class with your new  modified class    Thanks to http   blog naver com techshare 100145191355 and https   gist github com DalSoft 1588818 for pointing me in the right direction for how to do this  The last link on the first site contains full source code for the solution

User · Answer

if this maxJsonLength value is a int then how big is its int 32bit 64bit 16bit     i just want to be sure whats the maximum value i can set as my maxJsonLength   lt scripting gt           lt webServices gt               lt jsonSerialization maxJsonLength  2147483647  gt               lt  jsonSerialization gt           lt  webServices gt       lt  scripting gt

User · Answer

We don t need any server side changes  you can fix this only modify by web config file This helped for me  try this out   lt appSettings gt    lt add key  aspnet MaxJsonDeserializerMembers  value  2147483647    gt   lt add key  aspnet UpdatePanelMaxScriptLength  value  2147483647    gt   lt  appSettings gt     and      lt system web extensions gt   lt scripting gt     lt webServices gt       lt jsonSerialization maxJsonLength  2147483647   gt     lt  webServices gt   lt  scripting gt

User · Answer

Just ran into this  I m getting over 6 000 records  Just decided I d just do some paging  As in  I accept a page number in my MVC JsonResult endpoint  which is defaulted to 0 so it s not necessary  like so   public JsonResult MyObjects int pageNumber   0    Then instead of saying   return Json  repository MyObjects ToList    JsonRequestBehavior AllowGet     I say   return Json  repository MyObjects OrderBy obj   gt  obj ID  Skip 1000   pageNumber  Take 1000  ToList    JsonRequestBehavior AllowGet     It s very simple  Then  in JavaScript  instead of this   function myAJAXCallback items           Do stuff here     I instead say   var pageNumber   0  function myAJAXCallback items        if items length    1000             Call same endpoint but add this to the end    pageNumber       pageNumber              Do stuff here     And append your records to whatever you were doing with them in the first place  Or just wait until all the calls finish and cobble the results together

User · Answer

use lib Newtonsoft Json dll  public string serializeObj dynamic json                return JsonConvert SerializeObject json

User · Answer

If you are encountering this sort of issue in View  you can use below method to resolve that  Here Iused Newtonsoft package     using Newtonsoft Json  lt script type  text javascript  gt      var partData    Html Raw JsonConvert SerializeObject ViewBag Part     lt  script gt

User · Answer

I followed vestigal s answer and got to this solution   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

It appears that there is no  unlimited  value  The default is 2097152 characters  which is equivalent to 4 MB of Unicode string data   As as already been observed  17 000 records are hard to use well in the browser  If you are presenting an aggregate view it may be much more efficient to do the aggregation on the server and transfer only a summary in the browser  For example  consider a file system brower  we only see the top of the tree  then emit further requestes as we drill down  The number of records returned in each request is comparatively small  A tree view presentation can work well for large result sets

[asp.net] Can I set an unlimited length for maxJsonLength in web.config?

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