Image Map / Hot Spot _ Point Plotting

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;

//for txt file manipulation
using System.IO;

public partial class _PointManager : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if(!Page.IsPostBack)
        {
            DirectoryInfo dirInfo = new DirectoryInfo(Server.MapPath("PointLists"));

            ImageList.DataSource = dirInfo.GetFiles("*.*");
            ImageList.DataBind();
        }
    }

    public void ImageList_ItemDataBound(Object sender , DataGridItemEventArgs e)
    {
        //First, make sure we're NOT dealing with a Header or Footer row
        if(e.Item.ItemType != ListItemType.Header && e.Item.ItemType != ListItemType.Footer)
        {
            //Now, reference the Button control that the Delete ButtonColumn has been rendered to
            Button deleteButton = (Button)e.Item.Cells[0].Controls[0];

            //We can now add the onclick event handler
            deleteButton.Attributes.Add("onclick", "javascript:return " + 
                       "confirm('Are you sure you want to delete the file " + 
                       DataBinder.Eval(e.Item.DataItem, "Name") + "?')");
        }
    }

    public void ImageList_DeleteFile(Object sender , DataGridCommandEventArgs e )
    {
        //First, get the filename to delete
        String fileName = ImageList.DataKeys[e.Item.ItemIndex].ToString();
        
        //retrive active point list
        String FNAME = Server.MapPath("ListActive.txt");
        StreamReader sr = File.OpenText(FNAME);
        String ActiveList = Server.MapPath(sr.ReadToEnd());
        sr.Close();

        if (fileName == ActiveList)
        {
            activeListMessage.Text = ": YOU CAN'T DELETE ACTIVE LIST :";
        }
        else
        {
            File.Delete(fileName);
            DirectoryInfo dirInfo = new DirectoryInfo(Server.MapPath("PointLists"));
            ImageList.DataSource = dirInfo.GetFiles("*.*");
            ImageList.DataBind();
        }
    }

    protected void Page_PreRender()
    {
        String upFolder = Server.MapPath("PointLists/");
        DirectoryInfo dir = new DirectoryInfo(upFolder);
        ImageList2.DataSource = dir.GetFiles("*.*");
        ImageList2.DataBind();
    }
    protected void MakePointListActive_Click(object sender, EventArgs e)
    {
        String PATH = "~//PointLists//" + ImageList2.SelectedValue;

        String FILENAME = Server.MapPath("ListActive.txt");

        StreamWriter sr = File.CreateText(FILENAME);
        sr.Write(PATH);
        sr.Close();
    }
}