验证域用户名密码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

using System.Runtime.InteropServices;    // 必要引用
using System.Security.Principal;     // 必要引用

public  partial  class trad_in_user_login : System.Web.UI.Page
{
     protected  void Page_Load( object sender, EventArgs e)
    {
        UserLoginForDomainDAO u =  new UserLoginForDomainDAO();
         var f = u.impersonateValidUser( " yzhao ",  "abc .com ",  " 123456 ");
        Response.Write(f.ToString());        
    }


     internal  class UserLoginForDomainDAO
    {
         public  const  int LOGON32_LOGON_INTERACTIVE =  2;
         public  const  int LOGON32_PROVIDER_DEFAULT =  0;

        WindowsImpersonationContext impersonationContext;

        [DllImport( " advapi32.dll ", CharSet = CharSet.Auto)]
         public  static  extern  int LogonUser(String lpszUserName,
                                          String lpszDomain,
                                          String lpszPassword,
                                           int dwLogonType,
                                           int dwLogonProvider,
                                           ref IntPtr phToken);
        [DllImport( " advapi32.dll ", CharSet = System.Runtime.InteropServices.CharSet.Auto, SetLastError =  true)]
         public  extern  static  int DuplicateToken(IntPtr hToken,
                                           int impersonationLevel,
                                           ref IntPtr hNewToken);
         /**/
         ///   <summary>
         ///  输入用户名、密码、登录域判断是否成功
         ///   </summary>
         ///   <example>
         ///  if (impersonateValidUser(UserName, Domain, Password)){}
         ///   </example>
         ///   <param name="userName"> 账户名称，如：string UserName = UserNameTextBox.Text; </param>
         ///   <param name="domain"> 要登录的域，如：string Domain   = DomainTextBox.Text; </param>
         ///   <param name="password"> 账户密码, 如：string Password = PasswordTextBox.Text; </param>
         ///   <returns> 成功返回true,否则返回false </returns>
         public  bool impersonateValidUser(String userName, String domain, String password)
        {
            WindowsIdentity tempWindowsIdentity;
            IntPtr token = IntPtr.Zero;
            IntPtr tokenDuplicate = IntPtr.Zero;

             if (LogonUser(userName, domain, password, LOGON32_LOGON_INTERACTIVE,
            LOGON32_PROVIDER_DEFAULT,  ref token) !=  0)
            {
                 if (DuplicateToken(token,  2,  ref tokenDuplicate) !=  0)
                {
                    tempWindowsIdentity =  new WindowsIdentity(tokenDuplicate);
                    impersonationContext = tempWindowsIdentity.Impersonate();
                     if (impersonationContext !=  null)
                         return  true;
                     else
                         return  false;
                }
                 else
                     return  false;
            }
             else
                 return  false;
        }

         public  void undoImpersonation()
        {
            impersonationContext.Undo();
        }

    }
}