我需要测试用户是否可以在实际尝试这样做之前写入文件夹。

我已经实现了以下方法(在c# 2.0中),它尝试使用Directory.GetAccessControl()方法检索文件夹的安全权限。

private bool hasWriteAccessToFolder(string folderPath)
{
    try
    {
        // Attempt to get a list of security permissions from the folder. 
        // This will raise an exception if the path is read only or do not have access to view the permissions. 
        System.Security.AccessControl.DirectorySecurity ds = Directory.GetAccessControl(folderPath);
        return true;
    }
    catch (UnauthorizedAccessException)
    {
        return false;
    }
}

当我在谷歌上搜索如何测试写访问权限时,没有这样的结果,而且在Windows中测试权限看起来非常复杂。我担心我过于简化了事情,这个方法并不健壮,尽管它似乎确实有效。

我测试当前用户是否具有写访问权限的方法是否正确?


当前回答

试试这个:

try
{
    DirectoryInfo di = new DirectoryInfo(path);
    DirectorySecurity acl = di.GetAccessControl();
    AuthorizationRuleCollection rules = acl.GetAccessRules(true, true, typeof(NTAccount));

    WindowsIdentity currentUser = WindowsIdentity.GetCurrent();
    WindowsPrincipal principal = new WindowsPrincipal(currentUser);
    foreach (AuthorizationRule rule in rules)
    {
        FileSystemAccessRule fsAccessRule = rule as FileSystemAccessRule;
        if (fsAccessRule == null)
            continue;

        if ((fsAccessRule.FileSystemRights & FileSystemRights.WriteData) > 0)
        {
            NTAccount ntAccount = rule.IdentityReference as NTAccount;
            if (ntAccount == null)
            {
                continue;
            }

            if (principal.IsInRole(ntAccount.Value))
            {
                Console.WriteLine("Current user is in role of {0}, has write access", ntAccount.Value);
                continue;
            }
            Console.WriteLine("Current user is not in role of {0}, does not have write access", ntAccount.Value);                        
        }
    }
}
catch (UnauthorizedAccessException)
{
    Console.WriteLine("does not have write access");
}

其他回答

我同意阿什的看法,应该没问题。或者,您也可以使用声明性CAS,如果它们没有访问权限,则实际上从一开始就阻止程序运行。

据我所知,我相信一些CAS特性在c# 4.0中可能不存在,不确定这是否是一个问题。

例如,对于所有用户(内置用户),此方法工作良好-享受。

public static bool HasFolderWritePermission(string destDir)
{
   if(string.IsNullOrEmpty(destDir) || !Directory.Exists(destDir)) return false;
   try
   {
      DirectorySecurity security = Directory.GetAccessControl(destDir);
      SecurityIdentifier users = new SecurityIdentifier(WellKnownSidType.BuiltinUsersSid, null);
      foreach(AuthorizationRule rule in security.GetAccessRules(true, true, typeof(SecurityIdentifier)))
      {
          if(rule.IdentityReference == users)
          {
             FileSystemAccessRule rights = ((FileSystemAccessRule)rule);
             if(rights.AccessControlType == AccessControlType.Allow)
             {
                    if(rights.FileSystemRights == (rights.FileSystemRights | FileSystemRights.Modify)) return true;
             }
          }
       }
       return false;
    }
    catch
    {
        return false;
    }
}

这应该是您所需要的全部内容,据我所知,您只需要捕获一个异常。

private static readonly byte[] TestArray = new byte[]{
    69, 70, 71, 72
};

private static bool IsFolderAccessible(string path) {
    var temp_path = Path.Combine(path, Path.GetRandomFileName());

    try {
        using (var file = File.Create(temp_path, TestArray.Length, FileOptions.DeleteOnClose)) {
            file.Write(TestArray, 0, TestArray.Length);
        }

        return true;
    } catch (UnauthorizedAccessException ex) {
        Log.Warn($"Error accessing file {temp_path}", ex);

        return false;
    }
}

我知道现在写这篇文章有点晚了,但是您可能会发现这段代码很有用。

string path = @"c:\temp";
string NtAccountName = @"MyDomain\MyUserOrGroup";

DirectoryInfo di = new DirectoryInfo(path);
DirectorySecurity acl = di.GetAccessControl(AccessControlSections.All);
AuthorizationRuleCollection rules = acl.GetAccessRules(true, true, typeof(NTAccount));

//Go through the rules returned from the DirectorySecurity
foreach (AuthorizationRule rule in rules)
{
    //If we find one that matches the identity we are looking for
    if (rule.IdentityReference.Value.Equals(NtAccountName,StringComparison.CurrentCultureIgnoreCase))
    {
        var filesystemAccessRule = (FileSystemAccessRule)rule;

        //Cast to a FileSystemAccessRule to check for access rights
        if ((filesystemAccessRule.FileSystemRights & FileSystemRights.WriteData)>0 && filesystemAccessRule.AccessControlType != AccessControlType.Deny)
        {
            Console.WriteLine(string.Format("{0} has write access to {1}", NtAccountName, path));
        }
        else
        {
            Console.WriteLine(string.Format("{0} does not have write access to {1}", NtAccountName, path));
        }
    }
}

Console.ReadLine();

把它放到一个控制台应用程序中,看看它是否满足你的需要。

http://www.codeproject.com/KB/files/UserFileAccessRights.aspx

非常有用的类,检查以下消息的改进版本。