Updating form fields as they are being saved

I have a form page that includes a query string. When this form is submitted, I would like to amend the comments column with the query string information. I have been able to build a string to add the query string so it is readable and call the correct record in the form data to update. I have been using examples from the documentation and this is what I have so far in my viewBiz_OnAfterSave function:

var currentUrl = RequestContext.CurrentURL.ToString(); if (currentUrl.IndexOf("xxx") > -1) { // Gets the class name of the 'xxx' form DataClassInfo formClass = DataClassInfoProvider.GetDataClassInfo(bi.FormClassID); string className = formClass.ClassName;

        // Loads the form's data
        ObjectQuery<BizFormItem> data = BizFormItemProvider.GetItems(className).TopN(1).OrderByDescending("xxx");

        // Checks whether the form contains any records
        if (!DataHelper.DataSourceIsEmpty(data))
        {
            var dataString = data.ToString();
            // Loops through the form's data records
            foreach (BizFormItem item in data)
            {
                xxx.LogEvent("I", "form data", "adding to comments", "COMMENTS: " + item.GetStringValue("Comments", ""));

                string commentsFieldValue = item.GetStringValue("Comments", "");

                string newComments = commentsFieldValue + InsertQueryString();

                item.SetValue("Comments", newComments);

                xxx.LogEvent("I", "logging", "comments", "ABout to update comments to : " + newComments);

                item.SubmitChanges(false);
            }
        }
    }

I added the xxx because I am not able to show some information. The logevents work correctly. However, the page never does the redirect to the confirmation page (so I am left with a blank screen) and the new comments do not get written to the database. Any help would be greatly appreciated.

Thanks, Jessica