upade and total in footer templae of repeter not working

Question

Dear sir,
I have making cart in my project every things went to right but update and total value not working I m also attaching my code ...check and help me as possible.

Soursr Code(HTML)

  <asp:Repeater ID="Repeater1" runat="server"  onitemcommand="cpRepeater_ItemCommand" >
        <HeaderTemplate >
        <table width="900px" border="1px">
        <tr>
        <td>Check</td>
        <td>Pic</td>
        <td>Product ID</td>
        <td>Emailid</td>
        <td>Size</td>
        <td>Color</td>
        <td>Price</td>
        <td>Quantity</td>
        <td>Cost</td>
        <td>Option</td>
        </tr>
     
        </HeaderTemplate>
        <ItemTemplate >
      
        <tr>
        <td><asp:CheckBox ID="CheckBoxDelete" runat="server" /></td>
      
        <td><asp:Label ID="lblid" Visible ="false" runat ="server" Text ='<%# DataBinder.Eval(Container.DataItem,"id") %>' ></asp:Label>
        <asp:Image ID ="imagei" runat ="server" Width ="100px" Height ="100px" ImageUrl ='<%# DataBinder.Eval(Container.DataItem,"imagepath") %>' /></td>
         <td><asp:Label ID="Label1" Visible ="true" runat ="server" Text ='<%# DataBinder.Eval(Container.DataItem,"productid") %>' ></asp:Label></td>
        <td><asp:Label ID="emailid" Visible ="true" runat ="server" Text ='<%# DataBinder.Eval(Container.DataItem,"emailid") %>' ></asp:Label></td>
        <td><asp:Label ID="size" Visible ="true" runat ="server" Text ='<%# DataBinder.Eval(Container.DataItem,"ssize") %>' ></asp:Label></td>
        <td><asp:Label ID="color" Visible ="true" runat ="server" Text ='<%# DataBinder.Eval(Container.DataItem,"color") %>' ></asp:Label></td>
        <td><asp:Label ID="price" Visible ="true" runat ="server" Text ='<%# DataBinder.Eval(Container.DataItem,"price") %>' ></asp:Label></td>
        <td><asp:Label ID="quantity" Visible ="true" runat ="server" Text ='<%# DataBinder.Eval(Container.DataItem,"quantity") %>' ></asp:Label>
         <asp:TextBox ID="txtName" BackColor="#d4d0c8" runat="server" Text='<%# DataBinder.Eval(Container.DataItem, "quantity")%>' Visible="false"></asp:TextBox></td>
        <td><asp:Label ID="totalcost" Visible ="true" runat ="server" Text ='<%# DataBinder.Eval(Container.DataItem,"totalcost") %>' ></asp:Label></td>
         <td ><asp:LinkButton ID="lnkEdit" runat="server" CommandName="edit" CommandArgument='<%# DataBinder.Eval(Container.DataItem, "id") %>'>Edit</asp:LinkButton>
            <asp:LinkButton Visible="false" ID="lnkUpdate" runat="server" CommandName="update" CommandArgument='<%# DataBinder.Eval(Container.DataItem, "id") %>'>Update</asp:LinkButton>
            <asp:LinkButton Visible="false" ID="lnkCancel" runat="server" CommandName="cancel" CommandArgument='<%# DataBinder.Eval(Container.DataItem, "id") %>'>Cancel</asp:LinkButton>
            <asp:LinkButton ID="lnkDelete" runat="server" CommandName="delete" OnClientClick='javascript:return confirm("Are you sure you want to delete?")'
            CommandArgument='<%# DataBinder.Eval(Container.DataItem, "id") %>'>Delete</asp:LinkButton></td>
        </tr>
      
        </ItemTemplate>
          <FooterTemplate>
          <tr>
        <td>
                        Total
                    </td>
                    <td>
                        <asp:Label ID="lblTotal" runat="server">0</asp:Label>
                    </td>
                </tr>
                </table>
            </FooterTemplate>
        </asp:Repeater>
         <asp:LinkButton ID="dellink" ForeColor="Black" runat="server" 
            OnClientClick='javascript:return confirm("Are you sure you want to delete?")'
            onclick="dellink_Click">Delete Selected</asp:LinkButton>


Client side code(C#)


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.Web.Caching;
using System.Data.SqlClient;

public partial class shoping : System.Web.UI.Page
{
    SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["constr"].ToString());
    int totalPrice = 0;
    SqlDataAdapter da;
    public static int SQty = 0;
    protected void Page_Load(object sender, EventArgs e)
    {
        username.Text = Request.QueryString["emailid"].ToString();
        bindrepeter();
        if (Session["emailid"] == null)
        {
            login.Text = "Login";

        }
        else
        {
            login.Text = "Logout";
        }

    }
    //display record//
    protected void bindrepeter()
    {
        SqlCommand cmd = new SqlCommand("select *  from cart where emailid='" + username.Text + "'", con);
        SqlDataAdapter da = new SqlDataAdapter(cmd);
        DataSet ds = new DataSet();
       
        da.Fill(ds, "cart");
        Repeater1.DataSource = ds;
        Repeater1.DataBind();
    }
    //edit and update record//
    protected void cpRepeater_ItemCommand(object source, RepeaterCommandEventArgs e)
    {
        LinkButton lnkUpdate = (LinkButton)e.Item.FindControl("lnkUpdate");
        LinkButton lnkCancel = (LinkButton)e.Item.FindControl("lnkCancel");
        LinkButton lnkEdit = (LinkButton)e.Item.FindControl("lnkEdit");
        LinkButton lnkDelete = (LinkButton)e.Item.FindControl("lnkDelete");
        Label totalcost = (Label)e.Item.FindControl("totalcost");
        Label price = (Label)e.Item.FindControl("price");
        Label lblemailid = (Label)e.Item.FindControl("emailid");
        Label lblrptID = (Label)e.Item.FindControl("lblid");
        TextBox txtName = (TextBox)e.Item.FindControl("txtName");
        CheckBox chkDelete = (CheckBox)e.Item.FindControl("CheckBoxDelete");
       
       
        if (e.CommandName == "edit")
        {
            lnkCancel.Visible = true;
            lnkUpdate.Visible = true;
            lnkEdit.Visible = false;
            txtName.Visible = true;
            lblemailid.Visible = false;

        }
        if (e.CommandName == "cancel")
        {
            bindrepeter();
        }
        if (e.CommandName == "update")
        {

            SqlCommand SqlCmd = new SqlCommand("update cart set quantity=@quantity  where id=@ID", con);
            SqlCmd.Parameters.Add("@quantity", SqlDbType.VarChar).Value = txtName.Text;
            SqlCmd.Parameters.Add("@ID", SqlDbType.VarChar).Value = e.CommandArgument;
            try
            {
                con.Open();
                if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem)
                {
                    totalPrice = totalPrice + Convert.ToInt32(((Label)e.Item.FindControl("price")).Text);
                }
                SqlCmd.ExecuteNonQuery();

            }
            catch (Exception ex)
            {
                ex.Message.ToString();
            }
            finally
            {
                if (con.State == ConnectionState.Open)
                    con.Close();
            }
            bindrepeter();
        }
        if (e.CommandName == "delete")
        {

            SqlCommand SqlCmd = new SqlCommand("delete cart where id=@ID", con);
            SqlCmd.Parameters.Add("@ID", SqlDbType.VarChar).Value = e.CommandArgument;
            try
            {
                con.Open();
                SqlCmd.ExecuteNonQuery();

            }
            catch (Exception ex)
            {
                ex.Message.ToString();
            }
            finally
            {
                if (con.State == ConnectionState.Open)
                    con.Close();
            }
            bindrepeter();
        }

    }
    void Repeater1_PreRender(object sender, EventArgs e)
    {
        Label lblTotal = (Label)Repeater1.Controls[Repeater1.Controls.Count - 1].FindControl("lblTotal");
        lblTotal.Text = totalPrice.ToString();
    }

    protected void dellink_Click(object sender, EventArgs e)
    {
        foreach (RepeaterItem Item in Repeater1.Items)
        {
            CheckBox chkDelete = (CheckBox)Item.FindControl("CheckBoxDelete");
            Label lblrptID = (Label)Item.FindControl("lblid");

            if (chkDelete.Checked)
            {

                SqlCommand SqlCmd = new SqlCommand("delete cart where id=@ID", con);
                SqlCmd.Parameters.Add("@ID", SqlDbType.VarChar).Value = lblrptID.Text;
                SqlCmd.Connection = con;
                con.Open();
                SqlCmd.ExecuteNonQuery();
                con.Close();

            }
        }
        bindrepeter();
    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        if (CheckBox1.Checked == true)
        {

            Response.Redirect("~/ddorcheque.aspx?emailid=" + username.Text);
        }

        if (CheckBox2.Checked == true)
        {

            Response.Redirect("~/cash on delivery.aspx?emailid=" + username.Text);
        }
    }
    protected void sighup_Click(object sender, EventArgs e)
    {
        if (Session["emailid"] == null)
        {
            Response.Redirect("userregister.aspx");
        }
        else
        {
            Response.Redirect("useraccount.aspx?emailid=" + Session["emailid"].ToString());
        }

    }
    protected void login_Click(object sender, EventArgs e)
    {
        if (Session["emailid"] == null)
        {
            Response.Redirect("userlogin.aspx");
        }
        else
        {
            Session.Abandon();
            Session.Clear();
            Response.Redirect("Default.aspx");
        }
    }
    protected void account_Click(object sender, EventArgs e)
    {
        if (Session["emailid"] == null)
        {
            Response.Redirect("userlogin.aspx");
        }
        else
        {
            Response.Redirect("useraccount.aspx?emailid=" + Session["emailid"].ToString());
        }
    }
    protected void viewcart_Click(object sender, EventArgs e)
    {
        if (Session["emailid"] == null)
        {
            Response.Redirect("userlogin.aspx");
        }
        else
        {
            Response.Redirect("useraccount.aspx?emailid=" + Session["emailid"].ToString());
        }
    }

}