In ASP.NET how can I retrieve data from a specific control that is within a datalist

<%@ Page Title="" Language="C#" MasterPageFile="~/Student/MasterPage.master" AutoEventWireup="true" CodeFile="DataList.aspx.cs" Inherits="Student_DataList" %>

<%--<asp:Content ID="Content1" ContentPlaceHolderID="title" Runat="Server">

--%>
<asp:Content ID="Content2" ContentPlaceHolderID="head" Runat="Server">
<script language="C#" runat="server">

void ImageButton_Click(object sender, ImageClickEventArgs e)
{

ImageButton img = (ImageButton)sender;
DataListItem item = (DataListItem)img.NamingContainer;
if (item != null)
{

int itemIndex = item.ItemIndex;

string replyText = ((TextBox)this.DataList1.Items[item.ItemIndex].FindControl("replyBox")).Text;
Session["Description"] = replyText;
}

Response.Redirect("ViewMealDetails.aspx");

}

</script>

<asp:Content ID="Content3" ContentPlaceHolderID="contentBod" runat="Server">

<div>
<asp:DataList ID="DataList1" runat="server"
CellPadding="3" CellSpacing="2"
Font-Names="Verdana" Font-Size="Small" GridLines="Both" RepeatColumns="3" RepeatDirection="Horizontal"
Width="946px">
<footerstyle backcolor="#F7DFB5" forecolor="#8C4510">
<HeaderStyle BackColor="#333333" Font-Bold="True" Font-Size="Large" ForeColor="White"
HorizontalAlign="Center" VerticalAlign="Middle" />
<HeaderTemplate>
Breakfast Meals
</HeaderTemplate>
<itemstyle backcolor="white" forecolor="black" borderwidth="2px">
<itemtemplate>

<asp:ImageButton id="imagebutton1" runat="server"
AlternateText="ImageButton 1"
ImageAlign="left"
ImageUrl='<% # Bind("MealPicture", "../{0}")%>'
OnClick="ImageButton_Click" Height="250px" Width="315px"/>
Description:
<asp:Label ID="lblDescription" runat="server" Text='<%# Bind("Description") %>'>
<br />

Cost:
<asp:Label ID="lblCost" runat="server" Text='<%# Bind("Cost") %>'>                       
<asp:Button ID="btnAdd" runat="server" type="button" style="background-color: orange" Text="Add to order" PostBackUrl="~/Student/ViewMealDetails.aspx" />



</div>

I have copied and pasted all the markup code with the image button click object inside it. Take a look at my comment above.