using System;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;public partial class _Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        if (File1.PostedFile.FileName.Length == 0)
        {
            ClientScript.RegisterStartupScript(this.GetType(), "", "alert('请先选择一个文件!')", true);        }
        else
        {
            string SavePath = @"E:\temp\";
            if (!Directory.Exists(SavePath))
            {
                string message = "<h1>The upload path doesn't exist: {0}</h1>";
                Response.Write(string.Format(message, SavePath));
                Response.End();
            }            if (File1.PostedFile != null)
            {
                string filename = Path.GetFileName(File1.Value);
                SavePath += filename;
                File1.PostedFile.SaveAs(SavePath);                Page.ClientScript.RegisterStartupScript(this.GetType(), "", "alert('上传成功!');", true);
            }
            else
            {
                Page.ClientScript.RegisterStartupScript(this.GetType(), "", "alert('上传失败!');", true);
            }
        }
    }
}调试运行以后提示当前上下文中不存在Directory和名称path。是怎么回事 应该怎么改正?