Remove View State from UpdatePanel Call

Friday, January 27, 2012

You may not be aware that view state (and control state) is included on each UpdatePanel call, even if the controls placed inside it have it disabled. As view state can get quite large, it may be useful to disable posting it during UpdatePanel calls, as long as you know what you are doing!

Here’s one possible solution, using Microsoft’s AJAX Library to intercept the asynchronous call before it is actually sent to the server:

function removeViewState(body)

{

    var builder = new Sys.StringBuilder();

    var parts = body.split('&');

  

    for (var i = 0; i < parts.length; ++i)

    {

        if (parts[i].indexOf('__VIEWSTATE=') < 0)

        {

            builder.append(parts[i]);

        }

  

        if (i != parts.length - 1)

        {

            builder.append('&');

        }

    }

  

    return (builder.toString());

}

  

Sys.Net.WebRequestManager.add_invokingRequest

(

    function (s, e)

    {

        var webRequest = e.get_webRequest();

        var body = webRequest.get_body();

  

        body = removeViewState(body);

  

        webRequest.set_body(body);

    }

);