Having Problem in DATAGRID in ASP.NET

    }
    protected void editdata(object source, DataGridCommandEventArgs e)
    {
        x.EditItemIndex = e.Item.ItemIndex;
        bind_data();
    }
    public void bind_data()
    {
        SqlConnection conn = new SqlConnection("server=CHN-W2K-SYS067;uid=sa;pwd=;Database=pubs");
        conn.Open();
        SqlCommand cmd = new SqlCommand("SELECT * FROM Titles", conn);
        x.DataSource = cmd.ExecuteReader();
        x.DataBind();
    }
    protected void canceldata(object source, DataGridCommandEventArgs e)
    {
        x.EditItemIndex = -1;
        bind_data();
    }
    protected void updatedata(object source, DataGridCommandEventArgs e)
    {
        TextBox newtitle = new TextBox();
       // string titleid = x.DataKeys[e.Item.ItemIndex].ToString();
        newtitle =(TextBox) e.Item.Cells[0].Controls[0];
        Response.Write(newtitle.Text);
       
    }
}

Here is the code for default.aspx :