请教一个关于Directory的问题

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.IO;public partial class listdir : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        string strDir2List = Request.QueryString.Get("dir");
        Directory thisOne = null;//错误 1 无法声明静态类型“System.IO.Directory”的变量
        try
        {
            thisOne = new Directory(strDir2List); //错误 2 无法创建静态类“System.IO.Directory”的实例
            Response.Write("<p>Creation:" + 
                thisOne.CreationTime.ToString() + "</p>");
            Directory[] subDirectories = thisOne.GetDirectories();//错误 3 “System.IO.Directory”并不包含“CreationTime”的定义             Response.Write("<ul>");
            for (int i = 0; i < subDirectories.Length; i++)
            {
                Response.Write("<li><a href=\"listdir.aspx?dir=");
                Response.Write(Server.UrlEncode(subDirectories[i].FullName));
                Response.Write("\">" + subDirectories[i].Name);
                Response.Write("</a><br>");
            }
            Response.Write("</ul>");
            File[] theFiles = thisOne.GetFile();
            Response.Write("</ul>");
            for (int i = 0; i < theFiles.Length; i++)
            {
                Response.Write("<li><a href=\"showfile.aspx?file=");
                Response.Write(Server.UrlEncode(theFiles[i].FullName));
                Response.Write("\">" + theFiles[i].Name);
                Response.Write("</a><br>");
            }
            Response.Write("</ul>");
        }
        catch (Exception e)
        {
            Response.Write("Access not possible, error:<i>");
            Response.Write(e.ToString()+"</i>");
            Response.End();
        }
    }
}
以上代码有14处错误,希望高手赐教!