你可以把这一行写进Controller

json.MaxJsonLength = 2147483644;

您也可以将这一行写入web.config

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

`

为了安全起见，两者都用。

你可以把这一行写进Controller

json.MaxJsonLength = 2147483644;

您也可以将这一行写入web.config

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

`

为了安全起见，两者都用。

我在ASP中遇到了这个问题。NET Web表单。它完全忽略了网络。配置文件设置，所以我这样做:

        JavaScriptSerializer serializer = new JavaScriptSerializer();

        serializer.MaxJsonLength = Int32.MaxValue; 

        return serializer.Serialize(response);

当然，总的来说，这是一种糟糕的做法。如果您要在web服务调用中发送这么多数据，您应该考虑另一种方法。

如果你在视图中遇到这类问题，你可以使用下面的方法来解决。这里我用的是牛顿软包装。

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

您可以在web中配置json请求的最大长度。配置文件:

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

maxJsonLength的缺省值是102400。更多详细信息，请参见MSDN页面:http://msdn.microsoft.com/en-us/library/bb763183.aspx

我遵循了vestial的答案，得到了这个解决方案:

当我需要将一个大的json发送到控制器中的一个动作时，我会得到著名的“使用json JavaScriptSerializer进行反序列化期间错误”。字符串的长度超过maxJsonLength属性设置的值。\r\n参数名称:输入值提供程序”。

我所做的是创建一个新的ValueProviderFactory, LargeJsonValueProviderFactory，并设置MaxJsonLength = Int32。GetDeserializedObject方法中的MaxValue

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;
     }
  }
}

然后，在Global.asax.cs中的Application_Start方法中，用新的ValueProviderFactory替换ValueProviderFactory:

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);
}