private void RenderHiddenVariablesInUrl(HtmlMobileTextWriter writer)
 {
     if (Page.HasHiddenVariables())
     {
         String hiddenVariablePrefix = MobilePage.HiddenVariablePrefix;
         foreach (DictionaryEntry entry in Page.HiddenVariables)
         {
             writer.Write("&");
             writer.WriteUrlParameter(hiddenVariablePrefix + (String)entry.Key,
                                      (String)entry.Value);
         }
     }
 }
        /// <include file='doc\HtmlPageAdapter.uex' path='docs/doc[@for="HtmlPageAdapter.RenderUrlPostBackEvent"]/*' />
        public virtual void RenderUrlPostBackEvent(HtmlMobileTextWriter writer,
                                                   String target, 
                                                   String argument)
        {
            writer.WriteEncodedUrl(Page.RelativeFilePath);
            writer.Write("?");

            // Encode ViewStateID=.....&__ET=controlid&__EA=value in URL
            // Note: the encoding needs to be agreed with the page
            // adapter which handles the post back info
            String pageState = Page.ClientViewState;
            if (pageState != null)
            {
                writer.WriteUrlParameter(MobilePage.ViewStateID, pageState);
                writer.Write("&");
            }
            writer.WriteUrlParameter(EventSourceKey, target);
            writer.Write("&");
            writer.WriteUrlParameter(EventArgumentKey, argument);
            RenderHiddenVariablesInUrl(writer);

            // Unique file path suffix is used for identify if query
            // string text is present.  Corresponding code needs to agree
            // on this.  Even if the query string is empty, we still need
            // to output the suffix to indicate this. (this corresponds
            // to the code that handles the postback)
            writer.Write('&');
            writer.Write(Constants.UniqueFilePathSuffixVariable);

            String queryStringText = Page.QueryStringText;
            if (queryStringText != null && queryStringText.Length > 0)
            {
                writer.Write('&');
                writer.Write(queryStringText);
            }
        }