为什么我的程序中出现错误：“CS1501: 重载“Directory”方法未获取“1”参数”

[xazhlily]

具体的程序清单如下：
<% @ Page Language="C#"%>
<% @ Import Namespace="System.IO"%>
<%
string strDir2List = Request.QueryString.Get("dir");
Directory thisOne = null;
try
{
thisOne = new Directory(strDir2List);
Response.Write("<p>Creation:" + thisOne.CreationTime.ToString()+"</p>");
Directory[] subDirectories = thisOne.GetDircetories();
Response.Write("<ul>");
for(int i=0; i<subDirectories;i++)
{
Response.Write("<li><a href=\"Web004.aspx?dir=");
Response.Write(Server.UrlEncode(subDirectories[i].FullName));
Response.Write("\">"+subDirectories[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();
}
%>

[chenyuming2004]

string[] dir=Directory.GetDirectories(@"c;\winnt");

得到C盘WINNT文件夹的所有文件夹（不包括子目录）。