Cross Page Postback Without Circular Reference Errors

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

/* note the reference to the Interface below */
public partial class Admin_y : System.Web.UI.Page, ICommonPostback 
{
    #region Cross page postback var
    private int iItemID = -1;
    private int iClientUploadID = -1;
    public int IItemID
    {
        get { return iItemID; }
        set { iItemID = value; }
    }
    public int IClientUploadID
    {
        get { return iClientUploadID; }
        set { iClientUploadID = value; }
    }
    #endregion

    protected void Page_Load(object sender, EventArgs e)
    {
        if (PreviousPage != null)
        {
            ICommonPostback frm = PreviousPage as ICommonPostback;
            Label2.Text = frm.IItemID.ToString();
        } 
    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        iClientUploadID = 55;
        iItemID = 36;
    }
}