blocks|key|2973100|text|不幸的是，web.config设置为ignored+by+the+default+JsonResult+implementation。所以我猜你需要实现一个定制的json结果来解决这个问题。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|2973101|entityMap|0|LINK|mutability|MUTABLE|url|http://weblogs.asp.net/rashid/archive/2009/03/23/submitting-my-first-bug-after-asp-net-mvc-1-0-rtm-release.aspx^0|I|1C|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

Unfortunately the web.config setting is <a href="http://weblogs.asp.net/rashid/archive/2009/03/23/submitting-my-first-bug-after-asp-net-mvc-1-0-rtm-release.aspx" rel="noreferrer">ignored by the default JsonResult implementation</a>. So I guess you will need to implement a custom json result to overcome this issue.

blocks|key|271971|text|您也可以使用ContentResult作为suggested+here而不是JsonResult的子类化。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|271972|var+serializer+=+new+JavaScriptSerializer+{+MaxJsonLength+=+Int32.MaxValue,+RecursionLimit+=+100+};

return+new+ContentResult()
{
++++Content+=+serializer.Serialize(data),
++++ContentType+=+"application/json",
};|code-block|syntax|javascript|271973|entityMap|0|LINK|mutability|MUTABLE|url|http://msdn.microsoft.com/en-us/library/system.web.mvc.contentresult.aspx|1|http://dukelupus.wordpress.com/2011/05/10/asp-net-mvc-json-string-too-long-a-solution/|2|http://msdn.microsoft.com/en-us/library/system.web.mvc.jsonresult.aspx^0|6|D|12|A|6|D|0|L|E|1|12|A|2|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@$9|X|A|Y|B|C]|$9|Z|A|10|B|C]]|D|@$9|11|A|12|1|13]|$9|14|A|15|1|16]|$9|17|A|18|1|19]]|E|$]]|$1|F|3|G|5|H|7|1A|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|1B|8|@]|D|@]|E|$]]]|L|$M|$5|N|O|P|E|$Q|R]]|S|$5|N|O|P|E|$Q|T]]|U|$5|N|O|P|E|$Q|V]]]]

You could also use <a href="http://msdn.microsoft.com/en-us/library/system.web.mvc.contentresult.aspx" rel="noreferrer"><code>ContentResult</code></a> as <a href="http://dukelupus.wordpress.com/2011/05/10/asp-net-mvc-json-string-too-long-a-solution/" rel="noreferrer">suggested here</a> instead of subclassing <a href="http://msdn.microsoft.com/en-us/library/system.web.mvc.jsonresult.aspx" rel="noreferrer"><code>JsonResult</code></a>.

<pre class="lang-cs prettyprint-override"><code>var serializer = new JavaScriptSerializer { MaxJsonLength = Int32.MaxValue, RecursionLimit = 100 };

return new ContentResult()
{
 Content = serializer.Serialize(data),
 ContentType = "application/json",
};
</code></pre>

blocks|key|275460|text|这似乎已经在MVC4中得到了修复。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|275461|你可以这样做，这对我来说效果很好：|275462|public+ActionResult+SomeControllerAction()
{
++var+jsonResult+=+Json(veryLargeCollection,+JsonRequestBehavior.AllowGet);
++jsonResult.MaxJsonLength+=+int.MaxValue;
++return+jsonResult;
}|code-block|syntax|javascript|275463|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

It appears this has been fixed in MVC4.

You can do this, which worked well for me:

<pre><code>public ActionResult SomeControllerAction()
{
 var jsonResult = Json(veryLargeCollection, JsonRequestBehavior.AllowGet);
 jsonResult.MaxJsonLength = int.MaxValue;
 return jsonResult;
}
</code></pre>

blocks|key|269867|text|不需要自定义类。这就是我们所需要的：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|269868|return+new+JsonResult+{+Data+=+Result,+MaxJsonLength+=+Int32.MaxValue+};|code-block|syntax|javascript|269869|其中Result是您希望序列化的数据。|offset|length|style|CODE|269870|entityMap^0|0|0|2|6|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

No need for a custom class. This is all that is needed:

<pre><code>return new JsonResult { Data = Result, MaxJsonLength = Int32.MaxValue };
</code></pre>

where <code>Result</code> is that data you wish to serialize.

blocks|key|2973153|text|你可以尝试在你的LINQ表达式中只定义你需要的字段。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2973154|举例说明。假设您有一个具有Id、姓名、电话和json图片(字节数组)的模型，并且需要从json加载到选择列表中。|2973155|LINQ查询：|2973156|var+listItems+=+(from+u+in+Users+where+u.name.Contains(term)+select+u).ToList();|code-block|syntax|javascript|2973157|这里的问题是获取所有字段的"select+u“。所以，如果你有大图，布姆。|offset|length|style|BOLD|2973158|如何解决？非常非常简单。|2973159|var+listItems+=+(from+u+in+Users+where+u.name.Contains(term)+select+new+{u.Id,+u.Name}).ToList();|2973160|最佳做法是仅选择要使用的字段。|2973161|记住。这是一个简单的技巧，但可以帮助许多ASP.NET+MVC开发人员。|2973162|entityMap^0|0|0|0|0|E|8|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|11|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|12|8|@]|9|@]|A|$]]|$1|F|3|G|5|H|7|13|8|@]|9|@]|A|$I|J]]|$1|K|3|L|5|6|7|14|8|@$M|15|N|16|O|P]]|9|@]|A|$]]|$1|Q|3|R|5|6|7|17|8|@]|9|@]|A|$]]|$1|S|3|T|5|H|7|18|8|@]|9|@]|A|$I|J]]|$1|U|3|V|5|6|7|19|8|@]|9|@]|A|$]]|$1|W|3|X|5|6|7|1A|8|@]|9|@]|A|$]]|$1|Y|3|-4|5|6|7|1B|8|@]|9|@]|A|$]]]|Z|$]]

You can try define in your LINQ expression only the field's that you will need.

Example. Imagine that you have an Model with Id, Name, Phone and Picture (byte array) and need to load from json into an select list.

LINQ Query:

<pre><code>var listItems = (from u in Users where u.name.Contains(term) select u).ToList();
</code></pre>

The problem here is "select u" that get all fields. So, if you have big pictures, booomm.

How to solve? very, very simple.

<pre><code>var listItems = (from u in Users where u.name.Contains(term) select new {u.Id, u.Name}).ToList();
</code></pre>

The best practices is select only the field that you will use.

Remember. This is a simple tip, but can help many ASP.NET MVC developpers.

blocks|key|275478|text|如果使用Json.NET生成json字符串，则不需要设置MaxJsonLength的值。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|275479|return+new+ContentResult()
{
++++Content+=+Newtonsoft.Json.JsonConvert.SerializeObject(data),
++++ContentType+=+"application/json",
};|code-block|syntax|javascript|275480|entityMap|0|LINK|mutability|MUTABLE|url|http://www.newtonsoft.com/json^0|E|4|S|D|4|8|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]|$9|V|A|W|B|C]]|D|@$9|X|A|Y|1|Z]]|E|$]]|$1|F|3|G|5|H|7|10|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|11|8|@]|D|@]|E|$]]]|L|$M|$5|N|O|P|E|$Q|R]]]]

If use <a href="http://www.newtonsoft.com/json" rel="noreferrer">Json.NET</a> to generate the <code>json</code> string, it doesn't need to set <code>MaxJsonLength</code> value.

<pre><code>return new ContentResult()
{
 Content = Newtonsoft.Json.JsonConvert.SerializeObject(data),
 ContentType = "application/json",
};
</code></pre>

blocks|key|269899|text|我通过遵循这个+link解决了这个问题|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|269900|namespace+System.Web.Mvc
{
public+sealed+class+JsonDotNetValueProviderFactory+:+ValueProviderFactory
{
++++public+override+IValueProvider+GetValueProvider(ControllerContext+controllerContext)
++++{
++++++++if+(controllerContext+==+null)
++++++++++++throw+new+ArgumentNullException("controllerContext");

++++++++if+(!controllerContext.HttpContext.Request.ContentType.StartsWith("application/json",+StringComparison.OrdinalIgnoreCase))
++++++++++++return+null;

++++++++var+reader+=+new+StreamReader(controllerContext.HttpContext.Request.InputStream);
++++++++var+bodyText+=+reader.ReadToEnd();

++++++++return+String.IsNullOrEmpty(bodyText)+?+null+:+new+DictionaryValueProvider<object>(JsonConvert.DeserializeObject<ExpandoObject>(bodyText,+new+ExpandoObjectConverter()),+CultureInfo.CurrentCulture);
++++}
}

}

protected+void+Application_Start()
++++{
++++++++AreaRegistration.RegisterAllAreas();

++++++++RegisterGlobalFilters(GlobalFilters.Filters);
++++++++RegisterRoutes(RouteTable.Routes);

++++++++//Remove+and+JsonValueProviderFactory+and+add+JsonDotNetValueProviderFactory
++++++++ValueProviderFactories.Factories.Remove(ValueProviderFactories.Factories.OfType<JsonValueProviderFactory>().FirstOrDefault());
++++++++ValueProviderFactories.Factories.Add(new+JsonDotNetValueProviderFactory());
++++}|code-block|syntax|javascript|269901|entityMap|0|LINK|mutability|MUTABLE|url|http://www.dalsoft.co.uk/blog/index.php/2012/01/10/asp-net-mvc-3-improved-jsonvalueproviderfactory-using-json-net/^0|0|7|8|4|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@$9|V|A|W|1|X]]|E|$]]|$1|F|3|G|5|H|7|Y|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Z|8|@]|D|@]|E|$]]]|L|$M|$5|N|O|P|E|$Q|R]]]]

I solved the issue by following this <a href="http://www.dalsoft.co.uk/blog/index.php/2012/01/10/asp-net-mvc-3-improved-jsonvalueproviderfactory-using-json-net/" rel="nofollow">link</a>

<pre><code>namespace System.Web.Mvc
{
public sealed class JsonDotNetValueProviderFactory : ValueProviderFactory
{
 public override IValueProvider GetValueProvider(ControllerContext controllerContext)
 {
 if (controllerContext == null)
 throw new ArgumentNullException("controllerContext");

 if (!controllerContext.HttpContext.Request.ContentType.StartsWith("application/json", StringComparison.OrdinalIgnoreCase))
 return null;

 var reader = new StreamReader(controllerContext.HttpContext.Request.InputStream);
 var bodyText = reader.ReadToEnd();

 return String.IsNullOrEmpty(bodyText) ? null : new DictionaryValueProvider&lt;object&gt;(JsonConvert.DeserializeObject&lt;ExpandoObject&gt;(bodyText, new ExpandoObjectConverter()), CultureInfo.CurrentCulture);
 }
}

}

protected void Application_Start()
 {
 AreaRegistration.RegisterAllAreas();

 RegisterGlobalFilters(GlobalFilters.Filters);
 RegisterRoutes(RouteTable.Routes);

 //Remove and JsonValueProviderFactory and add JsonDotNetValueProviderFactory
 ValueProviderFactories.Factories.Remove(ValueProviderFactories.Factories.OfType&lt;JsonValueProviderFactory&gt;().FirstOrDefault());
 ValueProviderFactories.Factories.Add(new JsonDotNetValueProviderFactory());
 }
</code></pre>

blocks|key|3186998|text|在代码返回JsonResult对象之前，您需要手动读取配置节。只需在一行中从web.config读取：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3186999|++++++++var+jsonResult+=+Json(resultsForAjaxUI);
++++++++jsonResult.MaxJsonLength+=+(ConfigurationManager.GetSection("system.web.extensions/scripting/webServices/jsonSerialization")+as+System.Web.Configuration.ScriptingJsonSerializationSection).MaxJsonLength;
++++++++return+jsonResult;|code-block|syntax|javascript|3187000|确保在web.config中定义了配置元素|3187001|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

You need to read from the configuration section manually before your code returns a JsonResult object. Simply read from web.config in single line:

<pre><code> var jsonResult = Json(resultsForAjaxUI);
 jsonResult.MaxJsonLength = (ConfigurationManager.GetSection("system.web.extensions/scripting/webServices/jsonSerialization") as System.Web.Configuration.ScriptingJsonSerializationSection).MaxJsonLength;
 return jsonResult;
</code></pre>

Be sure you defined configuration element in web.config

blocks|key|3187027|text|替代ASP.NET+MVC+5修复：|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|3187028|在我的例子中，错误发生在请求过程中。在我的场景中，最好的方法是修改实际的JsonValueProviderFactory，这将修复应用到全局项目，并且可以通过编辑global.cs文件来完成。|CODE|3187029|JsonValueProviderConfig.Config(ValueProviderFactories.Factories);|code-block|syntax|javascript|3187030|添加web.config条目：|3187031|<add+key="aspnet:MaxJsonLength"+value="20971520"+/>|3187032|然后创建以下两个类|3187033|public+class+JsonValueProviderConfig
{
++++public+static+void+Config(ValueProviderFactoryCollection+factories)
++++{
++++++++var+jsonProviderFactory+=+factories.OfType<JsonValueProviderFactory>().Single();
++++++++factories.Remove(jsonProviderFactory);
++++++++factories.Add(new+CustomJsonValueProviderFactory());
++++}
}|3187034|这基本上是System.Web.Mvc中默认实现的精确副本，但增加了一个可配置的web.config应用设置值aspnet:MaxJsonLength。|3187035|public+class+CustomJsonValueProviderFactory+:+ValueProviderFactory
{

++++///+<summary>Returns+a+JSON+value-provider+object+for+the+specified+controller+context.</summary>
++++///+<returns>A+JSON+value-provider+object+for+the+specified+controller+context.</returns>
++++///+<param+name="controllerContext">The+controller+context.</param>
++++public+override+IValueProvider+GetValueProvider(ControllerContext+controllerContext)
++++{
++++++++if+(controllerContext+==+null)
++++++++++++throw+new+ArgumentNullException("controllerContext");

++++++++object+deserializedObject+=+CustomJsonValueProviderFactory.GetDeserializedObject(controllerContext);
++++++++if+(deserializedObject+==+null)
++++++++++++return+null;

++++++++Dictionary<string,+object>+strs+=+new+Dictionary<string,+object>(StringComparer.OrdinalIgnoreCase);
++++++++CustomJsonValueProviderFactory.AddToBackingStore(new+CustomJsonValueProviderFactory.EntryLimitedDictionary(strs),+string.Empty,+deserializedObject);

++++++++return+new+DictionaryValueProvider<object>(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<string,+object>+strs+=+value+as+IDictionary<string,+object>;
++++++++if+(strs+!=+null)
++++++++{
++++++++++++foreach+(KeyValuePair<string,+object>+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+<+lists.Count;+i%2B%2B)
++++++++{
++++++++++++CustomJsonValueProviderFactory.AddToBackingStore(backingStore,+CustomJsonValueProviderFactory.MakeArrayKey(prefix,+i),+lists[i]);
++++++++}
++++}

++++private+class+EntryLimitedDictionary
++++{
++++++++private+static+int+_maximumDepth;

++++++++private+readonly+IDictionary<string,+object>+_innerDictionary;

++++++++private+int+_itemCount;

++++++++static+EntryLimitedDictionary()
++++++++{
++++++++++++_maximumDepth+=+CustomJsonValueProviderFactory.GetMaximumDepth();
++++++++}

++++++++public+EntryLimitedDictionary(IDictionary<string,+object>+innerDictionary)
++++++++{
++++++++++++this._innerDictionary+=+innerDictionary;
++++++++}

++++++++public+void+Add(string+key,+object+value)
++++++++{
++++++++++++int+num+=+this._itemCount+%2B+1;
++++++++++++this._itemCount+=+num;
++++++++++++if+(num+>+_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+&&+values.Length+!=+0+&&+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+&&+values.Length+!=+0+&&+int.TryParse(values[0],+out+num))
++++++++++++{
++++++++++++++++return+num;
++++++++++++}
++++++++}
++++++++return+1000;
++++}
}|3187036|entityMap^0|0|I|0|10|O|29|9|0|0|0|0|0|0|5|E|1J|K|0|0^^$0|@$1|2|3|4|5|6|7|11|8|@$9|12|A|13|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|14|8|@$9|15|A|16|B|H]|$9|17|A|18|B|H]]|D|@]|E|$]]|$1|I|3|J|5|K|7|19|8|@]|D|@]|E|$L|M]]|$1|N|3|O|5|6|7|1A|8|@]|D|@]|E|$]]|$1|P|3|Q|5|K|7|1B|8|@]|D|@]|E|$L|M]]|$1|R|3|S|5|6|7|1C|8|@]|D|@]|E|$]]|$1|T|3|U|5|K|7|1D|8|@]|D|@]|E|$L|M]]|$1|V|3|W|5|6|7|1E|8|@$9|1F|A|1G|B|H]|$9|1H|A|1I|B|H]]|D|@]|E|$]]|$1|X|3|Y|5|K|7|1J|8|@]|D|@]|E|$L|M]]|$1|Z|3|-4|5|6|7|1K|8|@]|D|@]|E|$]]]|10|$]]

Alternative ASP.NET MVC 5 Fix:

In my case the error was occurring during the request. Best approach in my scenario is modifying the actual <code>JsonValueProviderFactory</code> which applies the fix to the global project and can be done by editing the <code>global.cs</code> file as such.

<pre><code>JsonValueProviderConfig.Config(ValueProviderFactories.Factories);
</code></pre>

add a web.config entry:

<pre><code>&lt;add key="aspnet:MaxJsonLength" value="20971520" /&gt;
</code></pre>

and then create the two following classes

<pre><code>public class JsonValueProviderConfig
{
 public static void Config(ValueProviderFactoryCollection factories)
 {
 var jsonProviderFactory = factories.OfType&lt;JsonValueProviderFactory&gt;().Single();
 factories.Remove(jsonProviderFactory);
 factories.Add(new CustomJsonValueProviderFactory());
 }
}
</code></pre>

This is basically an exact copy of the default implementation found in <code>System.Web.Mvc</code> but with the addition of a configurable web.config appsetting value <code>aspnet:MaxJsonLength</code>.

<pre><code>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;
 }
}
</code></pre>

blocks|key|3187069|text|在我将操作更改为[HttpPost]之前，上面的操作都不起作用。并将ajax类型设置为POST。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3187070|++++[HttpPost]
++++public+JsonResult+GetSelectedSignalData(string+signal1,...)
++++{
+++++++++JsonResult+result+=+new+JsonResult();
+++++++++var+signalData+=+GetTheData();
+++++++++try
+++++++++{
++++++++++++++var+serializer+=+new+System.Web.Script.Serialization.JavaScriptSerializer+{+MaxJsonLength+=+Int32.MaxValue,+RecursionLimit+=+100+};

++++++++++++result.Data+=+serializer.Serialize(signalData);
++++++++++++return+Json(result,+JsonRequestBehavior.AllowGet);
++++++++++++..
++++++++++++..
++++++++++++...

++++}|code-block|syntax|javascript|3187071|ajax调用为|3187072|$.ajax({
++++type:+"POST",
++++url:+some_url,
++++data:+JSON.stringify({++signal1:+signal1,..+}),
++++contentType:+"application/json;+charset=utf-8",
++++success:+function+(data)+{
++++++++if+(data+!==+null)+{
++++++++++++setValue();
++++++++}

++++},
++++failure:+function+(data)+{
++++++++$('#errMessage').text("Error...");
++++},
++++error:+function+(data)+{
++++++++$('#errMessage').text("Error...");
++++}
});|3187073|entityMap^0|8|A|17|4|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@$9|R|A|S|B|C]|$9|T|A|U|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|V|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|W|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|X|8|@]|D|@]|E|$I|J]]|$1|O|3|-4|5|6|7|Y|8|@]|D|@]|E|$]]]|P|$]]

None of the above worked out for me until I changed the Action as <code>[HttpPost]</code>. 
and made the ajax type as <code>POST</code>.

<pre><code> [HttpPost]
 public JsonResult GetSelectedSignalData(string signal1,...)
 {
 JsonResult result = new JsonResult();
 var signalData = GetTheData();
 try
 {
 var serializer = new System.Web.Script.Serialization.JavaScriptSerializer { MaxJsonLength = Int32.MaxValue, RecursionLimit = 100 };

 result.Data = serializer.Serialize(signalData);
 return Json(result, JsonRequestBehavior.AllowGet);
 ..
 ..
 ...

 }
</code></pre>

And the ajax call as

<pre><code>$.ajax({
 type: "POST",
 url: some_url,
 data: JSON.stringify({ signal1: signal1,.. }),
 contentType: "application/json; charset=utf-8",
 success: function (data) {
 if (data !== null) {
 setValue();
 }

 },
 failure: function (data) {
 $('#errMessage').text("Error...");
 },
 error: function (data) {
 $('#errMessage').text("Error...");
 }
});
</code></pre>

blocks|key|2973267|text|这对我很有效|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2973268|++++++++JsonSerializerSettings+json+=+new+JsonSerializerSettings
++++++++{
++++++++++++ReferenceLoopHandling+=+ReferenceLoopHandling.Ignore
++++++++};
++++++++var+result+=+JsonConvert.SerializeObject(list,+Formatting.Indented,+json);
++++++++return+new+JsonResult+{+Data+=+result,+MaxJsonLength+=+int.MaxValue+};|code-block|syntax|javascript|2973269|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

this worked for me

<pre><code> JsonSerializerSettings json = new JsonSerializerSettings
 {
 ReferenceLoopHandling = ReferenceLoopHandling.Ignore
 };
 var result = JsonConvert.SerializeObject(list, Formatting.Indented, json);
 return new JsonResult { Data = result, MaxJsonLength = int.MaxValue };
</code></pre>

blocks|key|272087|text|++++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
++++++++};
++++}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|272088|是我在MVC4中的解决方案。|unstyled|272089|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|J|8|@]|9|@]|A|$]]|$1|G|3|-4|5|F|7|K|8|@]|9|@]|A|$]]]|H|$]]

<pre><code> 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
 };
 }
</code></pre>

Was the fix for me in MVC 4.

blocks|key|2973320|text|还有一些其他的情况-数据从客户端发送到服务器。当你使用控制器方法并且模型很庞大时：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2973321|++++[HttpPost]
++++public+ActionResult+AddOrUpdateConsumerFile(FileMetaDataModelView+inputModel)
++++{
++++++++if+(inputModel+==+null)+return+null;
+++++....
++++}|code-block|syntax|javascript|2973322|系统抛出这样的异常：“使用JSON+JavaScriptSerializer序列化或反序列化时出错。字符串长度超过了maxJsonLength属性上设置的值。参数名称:+input”|2973323|在这种情况下，仅更改Web.config设置是不够的。您还可以覆盖mvc+json序列化程序以支持巨大的数据模型大小，或者手动从请求中反序列化模型。您的控制器方法将变为：|2973324|+++[HttpPost]
++++public+ActionResult+AddOrUpdateConsumerFile()
++++{
++++++++FileMetaDataModelView+inputModel+=+RequestManager.GetModelFromJsonRequest<FileMetaDataModelView>(HttpContext.Request);
++++++++if+(inputModel+==+null)+return+null;
++++++++......
++++}

+++public+static+T+GetModelFromJsonRequest<T>(HttpRequestBase+request)
++++{
++++++++string+result+=+"";
++++++++using+(Stream+req+=+request.InputStream)
++++++++{
++++++++++++req.Seek(0,+System.IO.SeekOrigin.Begin);
++++++++++++result+=+new+StreamReader(req).ReadToEnd();
++++++++}
++++++++return+JsonConvert.DeserializeObject<T>(result);
++++}|2973325|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|D|7|S|8|@]|9|@]|A|$E|F]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

there is a bit other case - data is sent from client to server.
when you are using controller method and model is huge :

<pre><code> [HttpPost]
 public ActionResult AddOrUpdateConsumerFile(FileMetaDataModelView inputModel)
 {
 if (inputModel == null) return null;
 ....
 }
</code></pre>

system throws exception like this "Error during serialization or deserialization using the JSON JavaScriptSerializer. The length of the string exceeds the value set on the maxJsonLength property. Parameter name: input"

Only changing Web.config settings is not enough to help in this case. You could additionally override mvc json serializer for supporting huge data model sizes or manually deserialize model from Request. Your controller method becomes:

<pre><code> [HttpPost]
 public ActionResult AddOrUpdateConsumerFile()
 {
 FileMetaDataModelView inputModel = RequestManager.GetModelFromJsonRequest&lt;FileMetaDataModelView&gt;(HttpContext.Request);
 if (inputModel == null) return null;
 ......
 }

 public static T GetModelFromJsonRequest&lt;T&gt;(HttpRequestBase request)
 {
 string result = "";
 using (Stream req = request.InputStream)
 {
 req.Seek(0, System.IO.SeekOrigin.Begin);
 result = new StreamReader(req).ReadToEnd();
 }
 return JsonConvert.DeserializeObject&lt;T&gt;(result);
 }
</code></pre>

blocks|key|273604|text|如果要从控制器返回view，并且希望在cshtml中以json编码的同时增加视图包数据的长度，则可以将此代码放在cshtml中。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|273605|@{
++++var+jss+=+new+System.Web.Script.Serialization.JavaScriptSerializer();
++++jss.MaxJsonLength+=+Int32.MaxValue;
++++var+userInfoJson+=+jss.Serialize(ViewBag.ActionObj);
}

var+dataJsonOnActionGrid1+=+@Html.Raw(userInfoJson);|code-block|syntax|javascript|273606|现在，可以在js页面上访问dataJsonOnActionGrid1，您将获得正确的结果。|offset|length|style|CODE|273607|谢谢|273608|entityMap^0|0|0|D|L|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@$I|T|J|U|K|L]]|9|@]|A|$]]|$1|M|3|N|5|6|7|V|8|@]|9|@]|A|$]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

You can put this code in cshtml if you are returning view from controller and you want to increase the length of view bag data while encoding in json in cshtml 

<pre><code>@{
 var jss = new System.Web.Script.Serialization.JavaScriptSerializer();
 jss.MaxJsonLength = Int32.MaxValue;
 var userInfoJson = jss.Serialize(ViewBag.ActionObj);
}

var dataJsonOnActionGrid1 = @Html.Raw(userInfoJson);
</code></pre>

Now, <code>dataJsonOnActionGrid1</code> will be accesible on js page and you will get proper result.

Thanks

blocks|key|270012|text|我很惊讶没有人建议使用结果过滤器。这是全局连接到操作/结果流水线的最干净的方式：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|270013|public+class+JsonResultFilter+:+IResultFilter
{
++++public+int?+MaxJsonLength+{+get;+set;+}

++++public+int?+RecursionLimit+{+get;+set;+}

++++public+void+OnResultExecuting(ResultExecutingContext+filterContext)
++++{
++++++++if+(filterContext.Result+is+JsonResult+jsonResult)
++++++++{
++++++++++++//+override+properties+only+if+they're+not+set
++++++++++++jsonResult.MaxJsonLength+=+jsonResult.MaxJsonLength+??+MaxJsonLength;
++++++++++++jsonResult.RecursionLimit+=+jsonResult.RecursionLimit+??+RecursionLimit;
++++++++}
++++}

++++public+void+OnResultExecuted(ResultExecutedContext+filterContext)
++++{
++++}
}|code-block|syntax|javascript|270014|然后，使用GlobalFilters.Filters注册该类的一个实例|offset|length|style|CODE|270015|GlobalFilters.Filters.Add(new+JsonResultFilter+{+MaxJsonLength+=+int.MaxValue+});|270016|entityMap^0|0|0|5|L|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@$I|T|J|U|K|L]]|9|@]|A|$]]|$1|M|3|N|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

I'm surprised no one has suggested using a result filter. This is the cleanest way to globally hook into the action/result pipeline:

<pre><code>public class JsonResultFilter : IResultFilter
{
 public int? MaxJsonLength { get; set; }

 public int? RecursionLimit { get; set; }

 public void OnResultExecuting(ResultExecutingContext filterContext)
 {
 if (filterContext.Result is JsonResult jsonResult)
 {
 // override properties only if they're not set
 jsonResult.MaxJsonLength = jsonResult.MaxJsonLength ?? MaxJsonLength;
 jsonResult.RecursionLimit = jsonResult.RecursionLimit ?? RecursionLimit;
 }
 }

 public void OnResultExecuted(ResultExecutedContext filterContext)
 {
 }
}
</code></pre>

Then, register an instance of that class using <code>GlobalFilters.Filters</code>:

<pre><code>GlobalFilters.Filters.Add(new JsonResultFilter { MaxJsonLength = int.MaxValue });
</code></pre>

In one of my controller actions I am returning a very large <code>JsonResult</code> to fill a grid.

I am getting the following <code>InvalidOperationException</code> exception:

Error during serialization or deserialization using the JSON JavaScriptSerializer. The length of the string exceeds the value set on the maxJsonLength property.

Setting the <code>maxJsonLength</code> property in the <code>web.config</code> to a higher value unfortunately does not show any effect.

<pre><code>&lt;system.web.extensions&gt;
 &lt;scripting&gt;
 &lt;webServices&gt;
 &lt;jsonSerialization maxJsonLength="2147483644"/&gt;
 &lt;/webServices&gt;
 &lt;/scripting&gt;
&lt;/system.web.extensions&gt;
</code></pre>

I don't want to pass it back as a string as mentioned in <a href="https://stackoverflow.com/questions/4155014/json-asp-net-mvc-maxjsonlength-problem/4155077#4155077">this</a> SO answer.

In my research I came across <a href="http://thoughtfulcode.wordpress.com/2011/01/03/custom-jsonresult-class-for-asp-net-mvc-to-avoid-maxjsonlength-exceeded-exception/" rel="noreferrer">this</a> blog post where writing an own <code>ActionResult</code> (e.g. <code>LargeJsonResult : JsonResult</code>) is recommended to bypass this behaviour.

Is this then the only solution? 
Is this a bug in ASP.NET MVC? 
Am I missing something?

Any help would be most appreciated.

MaxJsonLength exception in ASP.NET MVC during JavaScriptSerializer

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JSON

在我的一个控制器操作中，我返回了一个非常大的JsonResult来填充网格。我收到以下InvalidOperationException异常：使用JSON JavaScriptSerializer进行序列化或反序列化时出现错误。字符串的长度超过了在maxJsonLength属性上设置的值。遗憾的是，将web.confi...

问ASP.NET MVC在JavaScriptSerializer期间出现MaxJsonLength异常
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