用户模拟角色类。实现在程序段内进行用户角色模拟。(以前收集的资料，原始出处当时没记，请作者谅解)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;
using System.Security.Principal;

namespace TY.Framework
{

    ///   用户模拟角色类。实现在程序段内进行用户角色模拟。 
    ///  <example><![CDATA[使用的时候在你要执行特殊操作的代码段前面这样写：   
    ///         IdentityImpersonation   identityImpersonation   =   new   IdentityImpersonation("administrator", "yourpassword","yourhostname");   
    ///         identityImpersonation.BeginImpersonate();//开始管理员扮演   
    ///         //你的特殊操作   
    ///         ..   
    ///         .   
    ///       identityImpersonation.StopImpersonate();   //结束扮演]]>
    ///  </example>
    ///  
    public class IdentityImpersonation
    {

        [DllImport("advapi32.dll", SetLastError = true)]
        public static extern bool LogonUser(String lpszUsername, String lpszDomain, String lpszPassword, int dwLogonType, int dwLogonProvider, ref   IntPtr phToken);



        [DllImport("advapi32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        public extern static bool DuplicateToken(IntPtr ExistingTokenHandle, int SECURITY_IMPERSONATION_LEVEL, ref   IntPtr DuplicateTokenHandle);



        [DllImport("kernel32.dll", CharSet = CharSet.Auto)]
        public extern static bool CloseHandle(IntPtr handle);



        //   要模拟的用户的用户名、密码、域(机器名)   
        private String _sImperUsername;

        private String _sImperPassword;

        private String _sImperDomain;

        //   记录模拟上下文   
        private WindowsImpersonationContext _imperContext;

        private IntPtr _adminToken;

        private IntPtr _dupeToken;

        //   是否已停止模拟   
        private Boolean _bClosed;




        /// <summary>
        /// 构造函数
        /// </summary>
        /// <param name="impersonationUsername">所要模拟的用户的用户名</param>
        /// <param name="impersonationPassword">所要模拟的用户的密码</param>
        /// <param name="impersonationDomain">所要模拟的用户所在的域</param>
        public IdentityImpersonation(String impersonationUsername, String impersonationPassword, String impersonationDomain)
        {

            _sImperUsername = impersonationUsername;
            _sImperPassword = impersonationPassword;
            _sImperDomain = impersonationDomain;

            _adminToken = IntPtr.Zero;
            _dupeToken = IntPtr.Zero;
            _bClosed = true;

        }



        /// <summary>
        /// 析构函数
        /// </summary>
        ~IdentityImpersonation()
        {
            if (!_bClosed)
            {
                StopImpersonate();
            }
        }



        /// <summary>
        /// 开始身份角色模拟。   
        /// </summary>
        /// <returns></returns>


        public Boolean BeginImpersonate()
        {
            Boolean bLogined = LogonUser(_sImperUsername, _sImperDomain, _sImperPassword, 2, 0, ref   _adminToken);
            if (!bLogined)
            {
                return false;
            }
            Boolean bDuped = DuplicateToken(_adminToken, 2, ref   _dupeToken);
            if (!bDuped)
            {
                return false;
            }

            WindowsIdentity fakeId = new WindowsIdentity(_dupeToken);
            _imperContext = fakeId.Impersonate();
            _bClosed = false;
            return true;

        }


        /// <summary>
        /// 停止身分角色模拟。 
        /// </summary>
        public void StopImpersonate()
        {
            _imperContext.Undo();
            CloseHandle(_dupeToken);
            CloseHandle(_adminToken);
            _bClosed = true;

        }

    }
}