Cross Domain/Platform Authentication and Data Transfer

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;

public partial class AuthMaster : System.Web.UI.MasterPage
{
    public string TableWidth = "";
    protected void Page_Load(object sender, EventArgs e)
    {
        //default to SiteID="1"
        string SiteID = Request.QueryString["SiteID"] == null ? "1" : Request.QueryString["SiteID"].ToString();

        SiteInfo MySiteInfo = new SiteInfo();
        //use Session["SiteInfo"] to reduce database traffic. 
        //This is userful since many pages at the web site uses the same master page.
        try
        {
            if (Session["SiteInfo"] == null)
            {
                MySiteInfo.SiteID = int.Parse(SiteID);
                MySiteInfo.RetrieveSiteInfo();
                Session["SiteInfo"] = MySiteInfo;
            }
            else
            {
                MySiteInfo = (SiteInfo)Session["SiteInfo"];
                //check to see if SiteID in session is the same as the current. If changed, retrieve new site info
                if (MySiteInfo.SiteID != int.Parse(SiteID))
                {
                    MySiteInfo.SiteID = int.Parse(SiteID);
                    MySiteInfo.RetrieveSiteInfo();
                    Session["SiteInfo"] = MySiteInfo;
                }
            }

            ApplySiteStyle(MySiteInfo);
        }
        catch (Exception ex)
        {
            lblMasterPageError.Text=ex.Message.ToString();
        }
    }

    private void ApplySiteStyle(SiteInfo siteInfo)
    {
        MainStyle.Href = siteInfo.StyleSheetName;
        imgHeader.ImageUrl = siteInfo.HeaderImagePath;
        imgHeader.Width = Unit.Pixel((int)siteInfo.HeaderWidth);
        imgHeader.Height = Unit.Pixel((int)siteInfo.HeaderHeight);
        lblHeaderText.Text = siteInfo.HeaderText;
        TableWidth = (imgHeader.Width == 0 ? "800" : imgHeader.Width.ToString());
        DataBind();
    }
}