MaxJsonLength exception in ASP.NET MVC during JavaScriptSerializer

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

I am getting the following InvalidOperationException 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 maxJsonLength property in the web.config to a higher value unfortunately does not show any effect.

<system.web.extensions>
  <scripting>
    <webServices>
      <jsonSerialization maxJsonLength="2147483644"/>
    </webServices>
  </scripting>
</system.web.extensions>

I don't want to pass it back as a string as mentioned in this SO answer.

In my research I came across this blog post where writing an own ActionResult (e.g. LargeJsonResult : JsonResult) 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.

Solution 1:

It appears this has been fixed in MVC4.

You can do this, which worked well for me:

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

Solution 2:

You could also use ContentResult as suggested here instead of subclassing JsonResult.

var serializer = new JavaScriptSerializer { MaxJsonLength = Int32.MaxValue, RecursionLimit = 100 };

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

Solution 3:

Unfortunately the web.config setting is ignored by the default JsonResult implementation. So I guess you will need to implement a custom json result to overcome this issue.