How Do I Solve The Error

Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: index

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class CustomerView : System.Web.UI.Page
{
    Customer aCustomer = new Customer();
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            bind();
        }
    }

    protected void bind()
    {
        List<customer> customerList = new List<customer>();
        customerList = aCustomer.getCustomerAll();
        gvCustomer.DataSource = customerList;
        gvCustomer.DataBind();
    }

    protected void gvCustomer_SelectedIndexChanged(object sender, EventArgs e)
    {
        GridViewRow row = gvCustomer.SelectedRow;
        string CustID = row.Cells[0].Text;
        Response.Redirect("CustomerDetails.aspx?StaffID=" + CustID);
    }
    protected void gvCustomer_RowDeleting(object sender, GridViewDeleteEventArgs e)
    {
        int result = 0;
        Customer customer = new Customer();
        string CustID = gvCustomer.DataKeys[e.RowIndex].Value.ToString();
        result = customer.CustomerDelete(CustID);

        if (result > 0)
        {
            Response.Write("<script>alert('Customer Remove Sucessfully');</script>");
        }
        else
        {
            Response.Write("<script>alert('Customer Removal Not Sucessful');</script>");
        }

        Response.Redirect("CustomerView.aspx");
    }
    protected void gvCustomer_RowEditing(object sender, GridViewEditEventArgs e)
    {
        gvCustomer.EditIndex = e.NewEditIndex;
        bind();
    }
    protected void gvCustomer_RowCancelingEdit(object sender, GridViewCancelEditEventArgs e)
    {
        gvCustomer.EditIndex = -1;
        bind();
    }
    protected void gvCustomer_RowUpdating(object sender, GridViewUpdateEventArgs e)
    {
        int result = 0;
        Customer customer = new Customer();
        GridViewRow row = (GridViewRow)gvCustomer.Rows[e.RowIndex];
        string id = gvCustomer.DataKeys[e.RowIndex].Value.ToString();
        string tCustID = ((TextBox)row.Cells[0].Controls[0]).Text;
        string tCName = ((TextBox)row.Cells[1].Controls[0]).Text;
        string tCGender = ((TextBox)row.Cells[2].Controls[0]).Text;
        string tCDob = ((TextBox)row.Cells[3].Controls[0]).Text;
        string tCAddress = ((TextBox)row.Cells[4].Controls[0]).Text;
        string tCTelNo = ((TextBox)row.Cells[5].Controls[0]).Text;
        string tCEmail = ((TextBox)row.Cells[6].Controls[0]).Text;
        string tCPassword = ((TextBox)row.Cells[7].Controls[0]).Text;
        string tMailingList = ((TextBox)row.Cells[8].Controls[0]).Text;
        string tCUsername = ((TextBox)row.Cells[9].Controls[0]).Text;
        result = customer.CustomerUpdate(tCustID, tCName, tCGender, tCDob, tCAddress, tCTelNo, tCEmail, tCPassword, tMailingList, tCUsername);
        if (result > 0)
        {
            Response.Write("<script>alert('Customer updated successfully');</script>");
        }
        else
        {
            Response.Write("<script>alert('Customer NOT updated');</script>");
        }
        gvCustomer.EditIndex = -1;
        bind();
    }
    protected void btn_AddNewCustomer_Click(object sender, EventArgs e)
    {
        Response.Redirect("CustomerInsert.aspx");
    }
}