MaxJsonLength exception in ASP.NET MVC during JavaScriptSerializer

asp.net-mvc exception serialization jsonresult
Martin Buberl picture Martin Buberl · Apr 17, 2011 · Viewed 138.3k times · Source

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.

Answer

Orion Edwards picture Orion Edwards · Dec 19, 2012

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;
}

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