最近要实现访问远程主机的共享目录中的一个文件。遇到了权限问题。google了一下，找到了几种解决方法，记录如下：
一、调用net use命令
// 使用方法：
//if (Connect("192.168.1.48", "用户名", "密码"))
//{
// File.Copy(@"\\192.168.1.48\共享目录\test.txt", @"e:\\test.txt", true);
//}
public bool Connect(string remoteHost, string userName, string passWord)
{
bool Flag = true;
Process proc = new Process();
proc.StartInfo.FileName = "cmd.exe";
proc.StartInfo.UseShellExecute = false;
proc.StartInfo.RedirectStandardInput = true;
proc.StartInfo.RedirectStandardOutput = true;
proc.StartInfo.RedirectStandardError = true;
proc.StartInfo.CreateNoWindow = true;
try
{
proc.Start();
string command = @"net use \\" + remoteHost + " " + passWord + " " + " /user:" + userName + ">NUL";
proc.StandardInput.WriteLine(command);
command = "exit";
proc.StandardInput.WriteLine(command);
while (proc.HasExited == false)
{
proc.WaitForExit(1000);
}
string errormsg = proc.StandardError.ReadToEnd();
if (errormsg != "")
Flag = false;
proc.StandardError.Close();
}
catch (Exception ex)
{
Flag = false;
}
finally
{
proc.Close();
proc.Dispose();
}
return Flag;
}二、调用WNetAddConnection2、WNetAddConnection3或者NetUseAdd函数，进行磁盘映射。
using System;using System.Collections.Generic;using System.Text; using System.Runtime.InteropServices;
namespace WindowsApplication1{ public class MyMap { [DllImport("mpr.dll", EntryPoint = "WNetAddConnection2")] public static extern uint WNetAddConnection2( [In] NETRESOURCE lpNetResource, string lpPassword, string lpUsername, uint dwFlags); [DllImport("Mpr.dll")] public static extern uint WNetCancelConnection2( string lpName, uint dwFlags, bool fForce); [StructLayout(LayoutKind.Sequential)] public class NETRESOURCE { public int dwScope; public int dwType; public int dwDisplayType; public int dwUsage; public string LocalName; public string RemoteName; public string Comment; public string Provider; }
// remoteNetworkPath format: @"\\192.168.1.48\sharefolder" // localDriveName format: @"E:" public static bool CreateMap(string userName, string password, string remoteNetworkPath, string localDriveName) { NETRESOURCE myNetResource = new NETRESOURCE(); myNetResource.dwScope = 2; //2:RESOURCE_GLOBALNET myNetResource.dwType = 1; //1:RESOURCETYPE_ANY myNetResource.dwDisplayType = 3; //3:RESOURCEDISPLAYTYPE_GENERIC myNetResource.dwUsage = 1; //1: RESOURCEUSAGE_CONNECTABLE myNetResource.LocalName = localDriveName; myNetResource.RemoteName = remoteNetworkPath; myNetResource.Provider = null;
uint nret = WNetAddConnection2(myNetResource, password, userName, 0);
if (nret == 0) return true; else return false; }
// localDriveName format: @"E:" public static bool DeleteMap(string localDriveName) { uint nret = WNetCancelConnection2(localDriveName, 1, true);
if (nret == 0) return true; else return false; }
public void test() { // 注意： // remote、local、username的格式一定要正确，否则可能出现错误 string remote = @"\\192.168.1.48\generals"; string local = @"P:"; string username = @"Domain\UserName"; string password = @"Password"; bool ret = MyMap.CreateMap(username, password, remote, local); if (ret) { //do what you want: // ... //File.Copy("q:\\test.htm", "c:\\test.htm");
MyMap.DeleteMap(local); } } }}三、使用WebClient类
由于WebClient类可以上传下载文件，并且支持以http:、https:和file:开头的URI，所以可以用WebClient类来传输文件。
添加System.Net命名空间后使用如下代码下载文件：
private void Test1() { try { WebClient client = new WebClient(); NetworkCredential cred = new NetworkCredential("username", "password", "172.16.0.222"); client.Credentials = cred; client.DownloadFile("file://172.16.0.222/test/111.txt", "111.txt"); } catch (Exception ex) { // 如果网络很慢，而文件又很大，这时可能有超时异常（Time out）。 } }
public void Test2() { try { WebClient client = new WebClient(); NetworkCredential cred = new NetworkCredential("username", "password", "domain"); client.Credentials = cred; client.DownloadFile("file://172.16.0.222/test/111.txt", "111.txt"); } catch (Exception ex) { // 如果网络很慢，而文件又很大，这时可能有超时异常（Time out）。 } }类似的还可以试试WebRequest、FileWebRequest等：
WebRequest req = WebRequest.Create("file://138.12.12.14/generals/test.htm");
NetworkCredential cred = new NetworkCredential("username", "password", "IP");
req.Credentials = cred;
WebResponse response = req.GetResponse();
Stream strm = response.GetResponseStream();
StreamReader r = new StreamReader(strm);
... ...四、角色模拟
////// 身份模拟实现远程资源访问 /// public class FileImpersonation { // logon types const int LOGON32_LOGON_INTERACTIVE = 2; const int LOGON32_LOGON_NETWORK = 3; const int LOGON32_LOGON_NEW_CREDENTIALS = 9; // logon providers const int LOGON32_PROVIDER_DEFAULT = 0; const int LOGON32_PROVIDER_WINNT50 = 3; const int LOGON32_PROVIDER_WINNT40 = 2; const int LOGON32_PROVIDER_WINNT35 = 1; [DllImport("advapi32.dll", CharSet = CharSet.Auto, SetLastError = true)] public static extern int LogonUser(string lpszUserName, string lpszDomain, string lpszPassword, int dwLogonType, int dwLogonProvider, ref IntPtr phToken); [DllImport("advapi32.dll", CharSet = CharSet.Auto, SetLastError = true)] public static extern int DuplicateToken(IntPtr hToken, int impersonationLevel, ref IntPtr hNewToken); [DllImport("advapi32.dll", CharSet = CharSet.Auto, SetLastError = true)] public static extern bool RevertToSelf(); [DllImport("kernel32.dll", CharSet = CharSet.Auto)] public static extern bool CloseHandle(IntPtr handle); private WindowsImpersonationContext impersonationContext; ////// 身份模拟 /// /// 独立服务器用IP，域环境就用域名 /// /// ///public bool impersonateValidUser(string userName, string domain, string password) { WindowsIdentity tempWindowsIdentity; IntPtr token = IntPtr.Zero; IntPtr tokenDuplicate = IntPtr.Zero; if (RevertToSelf()) { // 这里使用LOGON32_LOGON_NEW_CREDENTIALS来访问远程资源。 // 如果要（通过模拟用户获得权限）实现服务器程序，访问本地授权数据库可 // 以用LOGON32_LOGON_INTERACTIVE if (LogonUser(userName, domain, password, LOGON32_LOGON_NEW_CREDENTIALS, LOGON32_PROVIDER_DEFAULT, ref token) != 0) { if (DuplicateToken(token, 2, ref tokenDuplicate) != 0) { tempWindowsIdentity = new WindowsIdentity(tokenDuplicate); impersonationContext = tempWindowsIdentity.Impersonate(); if (impersonationContext != null) { AppDomain.CurrentDomain.SetPrincipalPolicy(PrincipalPolicy.WindowsPrincipal); IPrincipal pr = System.Threading.Thread.CurrentPrincipal; IIdentity id = pr.Identity; CloseHandle(token); CloseHandle(tokenDuplicate); return true; } } } } if (token != IntPtr.Zero) CloseHandle(token); if (tokenDuplicate != IntPtr.Zero) CloseHandle(tokenDuplicate); return false; } /// /// 取消模拟身份 /// public void undoImpersonation() { impersonationContext.Undo(); } ////// /// /// 独立服务器用IP，域环境就用域名 /// /// /// 需要执行的操作 public void ImpersonateFunc(string username, string domain, string password, Action act) { bool isImpersonated = false; try { if (impersonateValidUser(username, domain, password)) { isImpersonated = true; //File.Copy(@"\\192.168.1.48\generals\now.htm", "c:\\now.htm", true); act(); } } catch (Exception ex) { Console.WriteLine(ex.ToString()); } finally { if (isImpersonated) undoImpersonation(); } } // } FileImpersonation imp = new FileImpersonation(); imp.ImpersonateFunc("Administrator", "192.168.0.125", "xxxx", () => { var source = new DirectoryInfo(@"D:\HR"); string targetFolder = @"\\192.168.0.125\d$\HR"; if (!Directory.Exists(targetFolder)) { Directory.CreateDirectory(targetFolder); } foreach (FileInfo item in source.GetFiles()) { string targertFile = Path.Combine(targetFolder, item.Name); File.Copy(item.FullName, targertFile, true); } });
五、比较
方法一通过调用Shell命令Net Use实现，有点笨拙。
方法二和方法一有些相似之处。映射远程资源，然后访问。
方法三由于会有超时异常出现，所以在网络速度快、传输小文件时是可以的。
方法四通过身份模拟实现远程资源访问。一些服务器进程就是通过这种方式运行的。这种方法也是我的最爱。
六、要注意的地方
关于这几种方法，google后都可以找到一些文章。但是等到自己实际测试时，有时会出现各种小错误，
这些错误基本来源于两方面：
1、函数的参数选择有问题，和自己的环境不相符。
比如
public static extern int LogonUser(String lpszUserName,
String lpszDomain,
String lpszPassword,
int dwLogonType,
int dwLogonProvider,
ref IntPtr phToken);中的dwLogonType，要访问远程资源就要用LOGON32_LOGON_NEW_CREDENTIALS，
要模拟本机用户就要用LOGON32_LOGON_INTERACTIVE。
2、函数的参数格式有问题。
a、比如
public static extern int LogonUser(String lpszUserName,
String lpszDomain,
String lpszPassword,
int dwLogonType,
int dwLogonProvider,
ref IntPtr phToken); 中的lpszUserName、lpszDomain、lpszPassword就要写清楚。
我就在这遇到过问题，第一次测试时，远程服务器就是一台独立的文件服务器，这是我的调用方式：
LogonUser("myname", "192.168.1.48", "password", LOGON32_LOGON_NEW_CREDENTIALS,
LOGON32_PROVIDER_DEFAULT, ref token);
第二次测试时，远程服务器是域MyDomain中的一个成员服务器，提供文件服务。这时代码就应该是：
LogonUser("myname", "MyDomain", "password", LOGON32_LOGON_NEW_CREDENTIALS,
LOGON32_PROVIDER_DEFAULT, ref token); 注意，代码中是MyDomain而不是IP地址。
b、再如：
参考上面代码
string remote = @"\\192.168.1.48\generals";
string local = @"P:";
string username = @"Domain\UserName";
string password = @"Password"; 如果@"\\192.168.1.48\generals"变成@"\\192.168.1.48\generals\”就会出错；
如果是域中的用户，那么把@"Domain\UserName"变成@"UserName"就会出错。
