.net怎么删除不为空的目录

.net怎么删除为空的目录  就是目录里面没有东西.希望快点回答我.我写的代码如下:
 //删除
        for (int i = 0; i < Repeater1.Items.Count; i++)
        {
            string id = ((HiddenField)Repeater1.Items[i].FindControl("HiddenField1")).Value;
            if (((CheckBox)Repeater1.Items[i].FindControl("CheckBox2")).Checked)
            {  
                string dir = ((HiddenField)Repeater1.Items[i].FindControl("HiddenField2")).Value;
                ssm.delete_sql_admin(Convert.ToInt32(id));
                ssm.delete_sql_two(Convert.ToInt32(id));
                ssm.delete_sql_three(Convert.ToInt32(id));
                //删除文件夹之前　　要先删除文件
                DirectoryInfo di = new DirectoryInfo(Server.MapPath(dir));
                if (di.Exists == true)
                {
                  //  di.Attributes=
                    di.Delete(true);//删除本机器上的文件夹,以及文件夹中的文件用DirectoryInfo就可以搞定了  
                }
                //还要删除ＩＩＳ上的目录名字
                try
                {
                    const String constIISWebSiteRoot = "IIS://localhost/W3SVC/1/ROOT";
                    DirectoryEntry root = new DirectoryEntry(constIISWebSiteRoot);
                    object[] paras = new object[2];
                    paras[0] = "IIsWebVirtualDir";
                    paras[1] = dir;
                    root.Invoke("Delete", paras);
                    root.CommitChanges();
                }catch(Exception ex){
                    Response.Write(ex.Message);
                }
            }
        }