Asp.net 我可以在web.config中设置maxJsonLength的无限长度吗？

我正在使用jQuery的自动完成功能。当我试图检索超过17000条记录（每条记录的长度不超过10个字符）的列表时，它超出了长度并抛出错误：

异常信息：
异常类型：InvalidOperationException
异常消息：使用JSON JavaScriptSerializer进行序列化或反序列化时出错。字符串的长度超过了maxJsonLength属性上设置的值

---

我可以在

web.config

中为

maxJsonLength

设置无限长度吗？如果没有，我可以设置的最大长度是多少？

注意：此答案仅适用于Web服务，如果您从控制器方法返回JSON，请确保您也阅读了下面的答案：

---

该属性不能是无限制的，它是一个默认为102400（100k）的整数属性

您可以在web.config上设置

MaxJsonLength

属性：

<configuration> 
   <system.web.extensions>
       <scripting>
           <webServices>
               <jsonSerialization maxJsonLength="50000000"/>
           </webServices>
       </scripting>
   </system.web.extensions>
</configuration> 

<configuration>
  <appSettings>
    <add key="aspnet:UpdatePanelMaxScriptLength" value="2147483647" />
  </appSettings>
</configuration>

---

您可以在web.config文件中配置json请求的最大长度：

<configuration>
    <system.web.extensions>
        <scripting>
            <webServices>
                <jsonSerialization maxJsonLength="....">
                </jsonSerialization>
            </webServices>
        </scripting>
    </system.web.extensions>
</configuration>

---

maxJsonLength的默认值为102400。有关更多详细信息，请参阅此MSDN页面：

问题是您是否真的需要返回17k条记录？您计划如何处理浏览器中的所有数据？用户无论如何都不会滚动浏览17000行

---

更好的方法是只检索“前几条”记录，并根据需要加载更多记录。

似乎没有“无限”值。默认值为2097152个字符，相当于4MB的Unicode字符串数据

---

正如已经观察到的，17000条记录很难在浏览器中很好地使用。如果要显示聚合视图，则在服务器上进行聚合并在浏览器中仅传输摘要可能会更有效。例如，考虑文件系统浏览器，我们只看到树的顶部，然后向下钻取更多的请求。每个请求中返回的记录数相对较少。树状视图演示可以很好地用于大型结果集。

如果在web.config中实现上述添加后，您得到“无法识别的配置节system.web.extensions”。错误，请尝试在

节中将其添加到web.config中：

            <sectionGroup name="system.web.extensions" type="System.Web.Extensions">
              <sectionGroup name="scripting" type="System.Web.Extensions">
                    <sectionGroup name="webServices" type="System.Web.Extensions">
                          <section name="jsonSerialization" type="System.Web.Extensions"/>
                    </sectionGroup>
              </sectionGroup>
        </sectionGroup>

---

如果您使用的是MVC4，请务必也签出

---

如果您仍然收到错误：

• 在web.config中将

  maxJsonLength

  属性设置为其最大值后
• 您知道数据的长度小于此值
• 而且您没有使用web服务方法进行JavaScript序列化

您的问题可能是：

MaxJsonLength属性的值仅适用于异步通信层用于调用Web服务方法的内部JavaScriptSerializer实例。（）

基本上，“internal”

JavaScriptSerializer

在从web方法调用时尊重

maxJsonLength

的值；直接使用

JavaScriptSerializer

（或通过MVC操作方法/控制器使用）不符合

maxJsonLength

属性，至少不符合web.config的

systemWebExtensions.scripting.webServices.jsonSerialization

部分。特别是，方法不遵守配置设置

作为一种解决方法，您可以在控制器内（或任何地方）执行以下操作：

---

这个答案是我的解释。

我修正了它

//your Json data here
string json_object="........";
JavaScriptSerializer jsJson = new JavaScriptSerializer();
jsJson.MaxJsonLength = 2147483644;
MyClass obj = jsJson.Deserialize<MyClass>(json_object);

//这里是您的Json数据
字符串json_object=“……”；
JavaScriptSerializer jsJson=新的JavaScriptSerializer（）；
jsJson.MaxJsonLength=2147483644；
MyClass obj=jsjsjson.Deserialize（json_对象）；

在MVC 4中，您可以执行以下操作：

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
    };
}

在你的控制器里

补充：

对于任何对需要指定的参数感到困惑的人，调用可能如下所示：

Json(
    new {
        field1 = true,
        field2 = "value"
        },
    "application/json",
    Encoding.UTF8,
    JsonRequestBehavior.AllowGet
);

---

您可以像其他人所说的那样在配置中进行设置，也可以在序列化程序的单个实例中进行设置，如：

var js = new JavaScriptSerializer() { MaxJsonLength = int.MaxValue };

---

对于那些在MVC3和JSON中遇到问题的人来说，JSON自动被反序列化为一个模型绑定器，并且太大，这里有一个解决方案

将JsonValueProviderFactory类的代码从MVC3源代码复制到新类中

在反序列化对象之前，添加一行更改JSON的最大长度

用新的修改类替换JsonValueProviderFactory类

---

感谢并为我指明了正确的方向。第一个站点上的最后一个链接包含解决方案的完整源代码。

刚刚遇到这个问题。我有6000多张唱片。我刚决定做一些传呼。如中所示，我在MVC JsonResult端点中接受一个页码，该页码默认为0，因此不需要，如下所示：

public JsonResult MyObjects(int pageNumber = 0)

而不是说：

return Json(_repository.MyObjects.ToList(), JsonRequestBehavior.AllowGet);

我说：

return Json(_repository.MyObjects.OrderBy(obj => obj.ID).Skip(1000 * pageNumber).Take(1000).ToList(), JsonRequestBehavior.AllowGet);

这很简单。然后，在JavaScript中，而不是：

function myAJAXCallback(items) {
    // Do stuff here
}

相反，我要说：

var pageNumber = 0;
function myAJAXCallback(items) {
    if(items.length == 1000)
        // Call same endpoint but add this to the end: '?pageNumber=' + ++pageNumber
    }
    // Do stuff here
}

---

并将您的记录附加到您最初使用它们所做的任何事情中。或者只需等待所有调用完成并将结果拼凑在一起。

如果您从MVC中的获取此错误，则可以通过将属性

MiniProfiler.Settings.MaxJsonResponseSize

设置为所需值来增加该值。默认情况下，此工具似乎会忽略配置中设置的值

MiniProfiler.Settings.MaxJsonResponseSize = 104857600;

---

礼貌。

我在ASP.NET Web表单中遇到了这个问题。它完全忽略了web.config文件

        JavaScriptSerializer serializer = new JavaScriptSerializer();

        serializer.MaxJsonLength = Int32.MaxValue; 

        return serializer.Serialize(response);

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();

json.MaxJsonLength = 2147483644;

<configuration>
  <system.web.extensions>
    <scripting>
        <webServices>
            <jsonSerialization maxJsonLength="2147483647">
            </jsonSerialization>
        </webServices>
    </scripting>
  </system.web.extensions>

public string serializeObj(dynamic json) {        
    return JsonConvert.SerializeObject(json);
}

<configuration>
  <appSettings>
    <add key="aspnet:UpdatePanelMaxScriptLength" value="2147483647" />
  </appSettings>
</configuration>

// 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 > 0) {
    serializer.MaxJsonLength = AppSettings.UpdatePanelMaxScriptLength;
}  

string attrText = serializer.Serialize(attrs);

   public ActionResult/JsonResult getData()
   {
      var jsonResult = Json(superlargedata, JsonRequestBehavior.AllowGet);
      jsonResult.MaxJsonLength = int.MaxValue;
      return jsonResult;
    }

JavaScriptSerializer serializer = new JavaScriptSerializer();
serializer.MaxJsonLength = Int32.MaxValue;

<scripting>
        <webServices>
            <jsonSerialization maxJsonLength="2147483647">
            </jsonSerialization>
        </webServices>
    </scripting>

public sealed class LargeJsonValueProviderFactory : ValueProviderFactory
{
private static void AddToBackingStore(LargeJsonValueProviderFactory.EntryLimitedDictionary backingStore, string prefix, object value)
{
    IDictionary<string, object> dictionary = value as IDictionary<string, object>;
    if (dictionary != null)
    {
        foreach (KeyValuePair<string, object> keyValuePair in (IEnumerable<KeyValuePair<string, object>>) 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 < 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);
}

/// <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 = LargeJsonValueProviderFactory.GetDeserializedObject(controllerContext);
    if (deserializedObject == null)
        return (IValueProvider) null;
    Dictionary<string, object> dictionary = new Dictionary<string, object>((IEqualityComparer<string>) StringComparer.OrdinalIgnoreCase);
    LargeJsonValueProviderFactory.AddToBackingStore(new LargeJsonValueProviderFactory.EntryLimitedDictionary((IDictionary<string, object>) dictionary), string.Empty, deserializedObject);
    return (IValueProvider) new DictionaryValueProvider<object>((IDictionary<string, object>) 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<string, object> _innerDictionary;
    private int _itemCount;

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

    public void Add(string key, object value)
    {
        if (++this._itemCount > 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 && values.Length > 0 && int.TryParse(values[0], out result))
                return result;
        }
        return 1000;
     }
  }
}

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);
}

[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 < 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;
            }
        }
    }
}

@using Newtonsoft.Json
<script type="text/javascript">
    var partData = @Html.Raw(JsonConvert.SerializeObject(ViewBag.Part));
</script>

JsonResult json= Json(classObject, JsonRequestBehavior.AllowGet);
json.MaxJsonLength = int.MaxValue;
return json;

<appSettings>
 <add key="aspnet:MaxJsonDeserializerMembers" value="2147483647" />
<add key="aspnet:UpdatePanelMaxScriptLength" value="2147483647" />
</appSettings>  

and   

<system.web.extensions>
<scripting>
  <webServices>
    <jsonSerialization maxJsonLength="2147483647"/>
  </webServices>
</scripting>

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
}

JsonValueProviderConfig.Config(ValueProviderFactories.Factories);

<add key="aspnet:MaxJsonLength" value="20971520" />

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

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++)
        {
            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 + 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;
    }
}

 JsonResult result = Json(r);
 result.MaxJsonLength = Int32.MaxValue;
 result.JsonRequestBehavior = JsonRequestBehavior.AllowGet;
 return result;

public JsonResult GetBigJson()
{
    var someBigObject = GetBigObject();
    return Json(someBigObject);
}

public JsonResult GetBigJson()
{
    var someBigObject = GetBigObject();
    return new JsonResult()
    {
        Data = someBigObject,
        JsonRequestBehavior = JsonRequestBehavior.DenyGet,
        MaxJsonLength = int.MaxValue
    };
}

protected internal JsonResult Json(object data)
{
    return Json(data, null /* contentType */, null /* contentEncoding */, JsonRequestBehavior.DenyGet);
}

protected internal virtual JsonResult Json(object data, string contentType, Encoding contentEncoding, JsonRequestBehavior behavior)
{
    return new JsonResult
    {
        Data = data,
        ContentType = contentType,
        ContentEncoding = contentEncoding,
        JsonRequestBehavior = behavior
    };
}

JavaScriptSerializer serializer = new JavaScriptSerializer();
if (MaxJsonLength.HasValue)
{
    serializer.MaxJsonLength = MaxJsonLength.Value;
}

if (RecursionLimit.HasValue)
{
    serializer.RecursionLimit = RecursionLimit.Value;
}

response.Write(serializer.Serialize(Data));