假如虚拟目录名为"chinabs"，先在项目中引用
System.DirectoryServices.dll，再
using System.DirectoryServices;
protected System.DirectoryServices.DirectoryEntry dirroot;

1、添加新的虚拟目录

     DirectoryEntry newVirDir = dirroot.Children.Add("chinabs","IIsWebVirtualDir");

     newVirDir.Invoke("AppCreate",true);

     newVirDir.CommitChanges();

     dirroot.CommitChanges();

2、更改虚拟目录属性

    //虚拟目录的属性较常用的有:AccessRead,AccessWrite,AccessExecute,AccessScript,DefaultDoc,EnableDefaultDoc,Path等

     DirectoryEntry Dirport = dirroot.Children.Find("chinabs","IIsVirtualDir");

     Dirport .Properties["AccessRead"][0] = true;
 

3、删除虚拟目录

      DirectoryEntry Dirport = dirroot.Children.Find("chinabs","IIsVirtualDir");

      Dirport.Invoke("AppDelete",true);

      dirroot.CommitChanges();

或者：

     object[] part = new object[2];

     part[0] = "IIsWebVirtualDir";

     part[1] = "chinabs";

     dirroot.Invoke("Delete",part);

     dirroot.CommitChanges();