Can I set an unlimited length for maxJsonLength in web.config?

Question

I am using the autocomplete feature of jQuery. When I try to retrieve the list of more then 17000 records (each won\'t have more than 10 char length), it\'s exceeding the le

Answer 1

If you are using MVC 4, be sure to check out this answer as well.

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If you are still receiving the error:

• after setting the maxJsonLength property to its maximum value in web.config
• and you know that your data's length is less than this value
• and you are not utilizing a web service method for the JavaScript serialization

your problem is is likely that:

The value of the MaxJsonLength property applies only to the internal JavaScriptSerializer instance that is used by the asynchronous communication layer to invoke Web services methods. (MSDN: ScriptingJsonSerializationSection.MaxJsonLength Property)

Basically, the "internal" JavaScriptSerializer respects the value of maxJsonLength when called from a web method; direct use of a JavaScriptSerializer (or use via an MVC action-method/Controller) does not respect the maxJsonLength property, at least not from the systemWebExtensions.scripting.webServices.jsonSerialization section of web.config.

As a workaround, you can do the following within your Controller (or anywhere really):

var serializer = new JavaScriptSerializer();

// For simplicity just use Int32's max value.
// You could always read the value from the config section mentioned above.
serializer.MaxJsonLength = Int32.MaxValue;

var resultData = new { Value = "foo", Text = "var" };
var result = new ContentResult{
    Content = serializer.Serialize(resultData),
    ContentType = "application/json"
};
return result;

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This answer is my interpretation of this asp.net forum answer.