ASP.NET

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
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;

public partial class Mycart : System.Web.UI.Page
{
    float total_Price = 0;
    int total_items = 0;
    int quanti;
    string pro_id;
    string desc;
    string id;
    int qty3;
    float unitprice;
    float cost;
    DataTable dt;
    DataTable dt2;
    DataGridItem dgItem;

    protected void Page_Load(object sender, EventArgs e)
    {
        if(!Page.IsPostBack)
        {
        if (Session["Cart"] == null)
        {
            dt = new DataTable();
            dt.Columns.Add("REF", typeof(string));
            dt.Columns.Add("Description", typeof(string));
            dt.Columns.Add("QTY", typeof(int));
            dt.Columns.Add("Price", typeof(float));
            dt.Columns.Add("Cost", typeof(float));
            get_data();
            Session["Cart"] = dt;
        }
        else
        {
            dt = (DataTable)Session["Cart"];
            get_data();
            Session["Cart"] = dt;
        }
        }
    }

    public void get_data()
    {
        pro_id = Request.QueryString["pr_id"];

        quanti = Convert.ToInt32(Request.QueryString["quant"]);

        if (pro_id != null)
        {
            SqlConnection con = new SqlConnection("Server=.; Database=eclsc; Trusted_Connection=yes");
            SqlCommand cmd = new SqlCommand();
            cmd.Connection = con;
            cmd.CommandText = "select ICEMACHINES.product_id,ICEMACHINES.sh_desc,ICEMACHINES.price from ICEMACHINES where ICEMACHINES.product_id LIKE @product_id union select GLASSWARE.product_id,GLASSWARE.sh_desc,GLASSWARE.price from GLASSWARE where GLASSWARE.product_id LIKE @product_id ";
            cmd.Parameters.Add("@product_id", SqlDbType.NVarChar, 50).Value = pro_id;
            cmd.Connection.Open();
            SqlDataReader rdr = cmd.ExecuteReader();
            ArrayList arRole1 = new ArrayList();

            while (rdr.Read())
            {
                desc = (rdr["sh_desc"]).ToString();
                id = (rdr["product_id"]).ToString();
                unitprice = Convert.ToSingle((rdr["price"]));
                cost = unitprice * quanti;

            }
            cmd.Connection.Close();

            DataRow myrow = dt.NewRow();
            myrow["REF"] = id;
            myrow["Description"] = desc;
            myrow["QTY"] = quanti;
            myrow["Price"] = unitprice;
            myrow["Cost"] = cost;

            dt.Rows.Add(myrow);
            dt.AcceptChanges();
            Session["data"]= dt;
            DataGrid2.DataSource = dt;
            DataGrid2.DataBind();
            
        }
        else
        {
            int a = 1;
        }
        total_items = total_items + quanti;
        total_Price = total_Price + cost;
        Session["items"] = total_items;
        Session["value"] = total_Price;
    }

    protected void BtnUpdate_Click(object sender, EventArgs e)
    {
        dt = (DataTable)Session["Cart"];
        CheckBox chkSelected = new CheckBox();

        foreach (DataGridItem dgItem in DataGrid2.Items)
        {
            chkSelected = (CheckBox)dgItem.FindControl("chkSelection");

            if (chkSelected.Checked == true)
            {
                TextBox TxtQTY = (TextBox)dgItem.Cells[2].FindControl("TxtQTY");
                int Txt2 = Convert.ToInt32(TxtQTY.Text);

                Label lblProduct_Id = (Label)dgItem.Cells[0].FindControl("lblProduct_Id");
                string id2 = lblProduct_Id.Text;

                Label lblDescription = (Label)dgItem.Cells[1].FindControl("lblDescription");
                string desc2 = lblDescription.Text;

                Label lblPrice = (Label)dgItem.Cells[3].FindControl("lblPrice");
                float price2 = Convert.ToSingle(lblPrice.Text);

                Label lblCost = (Label)dgItem.Cells[3].FindControl("lblCost");
                float cost2 = Convert.ToSingle(lblCost.Text);

                float final_cost = price2 * Txt2;
                
                  DataRow myrow = dt.NewRow();
                  myrow["REF"] = id2;
                  myrow["Description"] = desc2;
                  myrow["QTY"] = Txt2;
                  myrow["Price"] = price2;
                  myrow["Cost"] = final_cost;

                  dt.Rows.Add(myrow);
                  dt.AcceptChanges();
                  Session["data"] = dt;
            }

        }
        DataGrid2.DataSource = dt;
        DataGrid2.DataBind();
    }

    protected void BtnSave_Click(object sender, EventArgs e)
    {

    }

    protected void BtnRetrieve_Click(object sender, EventArgs e)
    {

    }

    protected void BtnContinue_Click(object sender, EventArgs e)
    {
        Response.Redirect("Default2.aspx");
    }

    protected void BtnCheckout_Click(object sender, EventArgs e)
    {
        Response.Redirect("Checkout.aspx");
    }
}

Menu1        
 |_ Menu1_1 
 |_ Menu1_2   

Menu2
      |_ Menu2_1
      |_ Menu2_2
             |_ Menu2_2_1     
             |_ Menu2_2_2

<br />
public class MyStuff(){<br />
<br />
}<br />

public partial class TaskEntry : System.Web.UI.Page
{
...
Global.TaskCategory = 0;
        Response.Redirect("TaskEntry.aspx");
...
}


public class Global
{
    public static int TaskCategory {
        get { return TaskCategory; }
        set { TaskCategory = value; } //breaks here!
    }
}

Error:
An unhandled exception 'system.stackoverflowexception' occurred.