如果访问被拒绝，我该如何检查子目录和/或文件是否被拒绝？

Question

I want to search and pass over directories or files that are access denied also in sub directories.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.IO;
using System.Security.AccessControl;
using System.Security.Principal;

namespace Search_Text_In_Files
{
    public partial class Form1 : Form
    {
        StreamWriter w = new StreamWriter(@"e:\textresults.txt");

        public Form1()
        {
            InitializeComponent();

            FindLines(@"E:\", "Green");
        }

        public List<string> FindLines(string DirName, string TextToSearch)
        {
            int counter = 0;
            List<string> findLines = new List<string>();
            DirectoryInfo di = new DirectoryInfo(DirName);
            if (di != null && di.Exists)
            {
                if (CheckFileForAccess(DirName) == true)
                {
                    foreach (string fi in Directory.GetFileSystemEntries(DirName,"*", SearchOption.AllDirectories))
                    {
                        if (string.Compare(fi.Extension, ".cs", true) == 0)
                        //|| string.Compare(fi.Extension, ".txt", true) == 0
                        //|| string.Compare(fi.Extension, ".text", true) == 0)
                        {
                            using (StreamReader sr = fi.OpenText())
                            {
                                string s = "";
                                while ((s = sr.ReadLine()) != null)
                                {
                                    if (s.Contains(TextToSearch))
                                    {
                                        counter++;
                                        findLines.Add(s);
                                        listView1.Items.Add(fi.Name);
                                        w.WriteLine("File Name: " + fi.Name);
                                        w.WriteLine("File Name Line: " + s);
                                        w.WriteLine(" ");
                                    }
                                }
                            }
                        }
                    }
                }
                w.Close();
            }
            return findLines;
        }

        private bool CheckForAccess(string PathName)
        {
            // Determine if the path is a file or a directory

            if (File.Exists(PathName) == true)
                return CheckFileForAccess(PathName);

            if (Directory.Exists(PathName) == true)
                return CheckFolderForAccess(PathName);

            return false;
        }


        private bool CheckFileForAccess(string FileName)
        {
            FileSecurity fs = new FileSecurity(FileName, AccessControlSections.Access);
            if (fs == null)
                return false;

            AuthorizationRuleCollection TheseRules = fs.GetAccessRules(true, true, typeof(NTAccount));
            if (TheseRules == null)
                return false;

            return CheckACL(TheseRules);
        }

        private bool CheckFolderForAccess(string FolderName)
        {
            DirectoryInfo di = new DirectoryInfo(FolderName);
            if (di == null)
                return false;

            DirectorySecurity acl = di.GetAccessControl(AccessControlSections.Access);
            if (acl == null)
                return false;

            AuthorizationRuleCollection TheseRules = acl.GetAccessRules(true, true, typeof(NTAccount));
            if (TheseRules == null)
                return false;

            return CheckACL(TheseRules);
        }

        private bool CheckACL(AuthorizationRuleCollection TheseRules)
        {
            foreach (FileSystemAccessRule ThisRule in TheseRules)
            {
                if ((ThisRule.FileSystemRights & FileSystemRights.Read) == FileSystemRights.Read)
                {
                    if (ThisRule.AccessControlType == AccessControlType.Deny)
                        return false;
                }
                // Run as many other checks as you like
            }

            return true;
        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }
    }
}

Before in the original this line:

foreach (string fi in Directory.GetFileSystemEntries(DirName,"*", SearchOption.AllDirectories))

Was

foreach (FileInfo fi in di.EnumerateFiles("*", SearchOption.AllDirectories))

I changed it to Directory.GetFileSystemEntries since i want to check for access denied also in sub directories too.

Answer 1

I recommend to use recursive call to look up the directory one by one on this problem to make the check of the directory access specifically limited to certain directory in check.

You can use DirectoryInfo.GetDirectories to check if a directory has a sub-directory before you do the recursive call.

This way, the code is cleaner, and you only need to pass a directory when it is not accessible.

Also, you can use Directory.GetAccessControl() to check if you have an access to a Directory before hand.