Validating form data in generic method

Hi all

I have a BasePage which all my pages inherit, and I want to have some security
checking on the Overridden PreInit Event, like this:

protected override void OnPreInit(EventArgs e) 
    {
        ValidateUrl();

        ValidateFormValues();

        CheckUserLoggedIn(); //etc etc
    }

 I my method for checking the url for malicious characters works great - and now
I want to do a similar thing for all posted data. Here's how I imagine it...

private void ValidateFormValues()
    {
        if (IsPostBack)
        {            
            Regex regMalacious = new
Regex(@"^[^<>`~!@#}%:;)(_^{&*=|']+$"); //should probably
test on accepted values instead, but you get the idea
            int errors = 0;

            System.Collections.Specialized.NameValueCollection formVals =
Request.Form;
            string[] keys = formVals.AllKeys;
            for (int i = 0; i < keys.Length; i++)
            {
                string name = keys[i].ToString();

                string value = formVals[name].ToString();

                if (!regMalacious.IsMatch(value))
                {
                    errors++;
                }
            }
            if (errors > 0)
            {
                //Log error & kick user off
            }

        }
    }

This seems to just about work, the only problem is that .Net has a lot of post
data such as __VIEWSTATE etc which contain all sorts of characters.

My questions are:

1. Is this is viable solution, or is there an 'industry standard' way of doing
this that i've missed?
2. If this is a suitable technique, what is the best way of eliminating the
built-in .net postback stuff? (I would need to distinguish them from my form
field data)

Thanks in advance

HI

I think the setting  ValidateRequest property of the Page to true( which iss the
default) must take care of all ...

<%@PageLanguage="C#"ValidateRequest="true"