访问AD问题:asp.net如何访问Active Directory获取域用户?
   AD(域控制器)在服务器A上,AP(web系统)在服务器B上, 
 域名称:dnssvr;   
 在局域网内的机器都加入域dnssvr,然后访问服务器B上的AP   
 请问在AP的首页该如何写代码获取访问此AP的用户并去AD验证?   
 谢谢各位先!
------解决方案-------------------- <%@ Page language= "c# " AutoEventWireup= "true " %>  
  <%@ Import Namespace= "System.Threading " %>  
  <%@ Import Namespace= "System.Security.Principal " %>  
  <HTML>  
  <HEAD>  
  <title> WhoAmI </title>  
  </HEAD>  
  <body>  
  <form id= "WhoAmI " method= "post " runat= "server ">  
  <TABLE id=contextTable border=1>  
  <TR>  
  <TD align=middle colSpan=3 rowSpan= " ">  
 HttpContext.Current.User.Identity </TD>  
  </TR>  
  <TR>  
  <TD>  <b> Name </b>  </TD>  
  <TD>  <asp:Label ID= "contextName " Runat=server />  </TD>  
  </TR>  
  <TR>  
  <TD>  <b> IsAuthenticated </b>  </TD>  
  <TD>  <asp:Label ID= "contextIsAuth " Runat=server />  </TD>  
  </TR>  
  <TR>  
  <TD>  <b> AuthenticationType </b>  </TD>  
  <TD>  <asp:Label ID= "contextAuthType " Runat=server />  </TD>  
  </TR>  
  </TABLE>  
  <br/>  <br/>    
  <TABLE id=windowsIdentityTable border=1>  
  <TR>  
  <TD align=middle colSpan=3 rowSpan= " "> WindowsIdentity.GetCurrent() </TD>  
  </TR>  
  <TR>  
  <TD>  <b> Name </b>  </TD>  
  <TD>  <asp:Label ID= "windowsName " Runat=server />  </TD>  
  </TR>  
  <TR>  
  <TD>  <b> IsAuthenticated </b>  </TD>  
  <TD>  <asp:Label ID= "windowsIsAuth " Runat=server />  </TD>  
  </TR>  
  <TR>  
  <TD>  <b> AuthenticationType </b>  </TD>  
  <TD>  <asp:Label ID= "windowsAuthType " Runat=server />  </TD>  
  </TR>  
  </TABLE>  
  <br/>  <br/>    
  <TABLE id=threadIdentityTable border=1>  
  <TR>  
  <TD align=middle colSpan=3  
 rowSpan= " "> Thread.CurrentPrincipal.Identity </TD>  
  </TR>  
  <TR>  
  <TD>  <b> Name </b>  </TD>  
  <TD>  <asp:Label ID= "threadName " Runat=server />  </TD>  
  </TR>  
  <TR>  
  <TD>  <b> IsAuthenticated </b>  </TD>  
  <TD>  <asp:Label ID= "threadIsAuthenticated " Runat=server />  </TD>  
  </TR>  
  <TR>  
  <TD>  <b> AuthenticationType </b>  </TD>  
  <TD>  <asp:Label ID= "threadAuthenticationType " Runat=server />  </TD>  
  </TR>  
  </TABLE>  
  </form>  
  </body>  
  </HTML>  
  <script runat=server>  
 void Page_Load(Object sender, EventArgs e) 
 { 
 IIdentity id = HttpContext.Current.User.Identity; 
 if(null != id) 
 { 
 contextName.Text = id.Name; 
 contextIsAuth.Text = id.IsAuthenticated.ToString(); 
 contextAuthType.Text = id.AuthenticationType; 
 } 
 id = Thread.CurrentPrincipal.Identity; 
 if(null != id) 
 { 
 threadName.Text = id.Name; 
 threadIsAuthenticated.Text = id.IsAuthentic