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

我也遇到了同样的问题:如何验证我是否可以在特定目录中读/写。我最终得到了一个简单的解决办法……实际测试一下。 以下是我简单而有效的解决方法。

 class Program
{

    /// <summary>
    /// Tests if can read files and if any are present
    /// </summary>
    /// <param name="dirPath"></param>
    /// <returns></returns>
    private genericResponse check_canRead(string dirPath)
    {
        try
        {
            IEnumerable<string> files = Directory.EnumerateFiles(dirPath);
            if (files.Count().Equals(0))
                return new genericResponse() { status = true, idMsg = genericResponseType.NothingToRead };

            return new genericResponse() { status = true, idMsg = genericResponseType.OK };
        }
        catch (DirectoryNotFoundException ex)
        {

            return new genericResponse() { status = false, idMsg = genericResponseType.ItemNotFound };

        }
        catch (UnauthorizedAccessException ex)
        {

            return new genericResponse() { status = false, idMsg = genericResponseType.CannotRead };

        }

    }

    /// <summary>
    /// Tests if can wirte both files or Directory
    /// </summary>
    /// <param name="dirPath"></param>
    /// <returns></returns>
    private genericResponse check_canWrite(string dirPath)
    {

        try
        {
            string testDir = "__TESTDIR__";
            Directory.CreateDirectory(string.Join("/", dirPath, testDir));

            Directory.Delete(string.Join("/", dirPath, testDir));


            string testFile = "__TESTFILE__.txt";
            try
            {
                TextWriter tw = new StreamWriter(string.Join("/", dirPath, testFile), false);
                tw.WriteLine(testFile);
                tw.Close();
                File.Delete(string.Join("/", dirPath, testFile));

                return new genericResponse() { status = true, idMsg = genericResponseType.OK };
            }
            catch (UnauthorizedAccessException ex)
            {

                return new genericResponse() { status = false, idMsg = genericResponseType.CannotWriteFile };

            }


        }
        catch (UnauthorizedAccessException ex)
        {

            return new genericResponse() { status = false, idMsg = genericResponseType.CannotWriteDir };

        }
    }


}

public class genericResponse
{

    public bool status { get; set; }
    public genericResponseType idMsg { get; set; }
    public string msg { get; set; }

}

public enum genericResponseType
{

    NothingToRead = 1,
    OK = 0,
    CannotRead = -1,
    CannotWriteDir = -2,
    CannotWriteFile = -3,
    ItemNotFound = -4

}

希望能有所帮助!

其他回答

以我之见,唯一100%可靠的测试是否可以写入目录的方法是实际写入并最终捕获异常。

您的代码获得给定目录的DirectorySecurity,并正确处理异常(由于您无法访问安全性信息)。然而,在您的示例中,您实际上并没有询问返回的对象以查看允许哪些访问—我认为您需要添加这一点。

Here is a modified version of CsabaS's answer, which accounts for explicit deny access rules. The function goes through all FileSystemAccessRules for a directory, and checks if the current user is in a role which has access to a directory. If no such roles are found or the user is in a role with denied access, the function returns false. To check read rights, pass FileSystemRights.Read to the function; for write rights, pass FileSystemRights.Write. If you want to check an arbitrary user's rights and not the current one's, substitute the currentUser WindowsIdentity for the desired WindowsIdentity. I would also advise against relying on functions like this to determine if the user can safely use the directory. This answer perfectly explains why.

    public static bool UserHasDirectoryAccessRights(string path, FileSystemRights accessRights)
    {
        var isInRoleWithAccess = false;

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

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

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

                    if (principal.IsInRole(ntAccount.Value))
                    {
                        if (fsAccessRule.AccessControlType == AccessControlType.Deny)
                            return false;
                        isInRoleWithAccess = true;
                    }
                }
            }
        }
        catch (UnauthorizedAccessException)
        {
            return false;
        }
        return isInRoleWithAccess;
    }

以上解决方案都很好,但对我来说,我发现这段代码简单可行。 只需要创建一个临时文件。如果创建了该文件,则该文件的平均用户具有写权限。

        public static bool HasWritePermission(string tempfilepath)
        {
            try
            {
                System.IO.File.Create(tempfilepath + "temp.txt").Close();
                System.IO.File.Delete(tempfilepath + "temp.txt");
            }
            catch (System.UnauthorizedAccessException ex)
            {

                return false;
            }

            return true;
        }

这是在c#中检查文件夹访问的一种非常有效的方法。它唯一可能失败的地方是,如果您需要在一个紧凑的循环中调用它,其中异常的开销可能是一个问题。

之前也有人问过类似的问题。