How to check if access is authorized or not for a directory in C#?

Question

I made a scan for files , directories & all methods which all use Directory.GetDirectories() & Directory.GetFiles() . The way it's setup now is

 // . . .
 string[] files;
 string[] dirs;

 try
 {
    files = Directory.GetFiles(path);
    dirs = Directory.GetDirectories(path);
 }
 catch
 {
    files = new string[0];
    dirs = new string[0];
 }
 //. . .

It works just fine but, I set a goal to write a library which wont contain try => catch in any of the methods so, i started searching on how to get directory permissions and the furthest i got was Directory.GetAccessControl(path) but don't know where to go from there. Is there a way to see if access to said directory is authorized or not?

Answer 1

Below is a program I wrote to write filenames to an xml file. It uses a recursive algorithm so go through each folder and subfolders. The reason I wrote the code to use a recursive algorithm is to allow the code to continue if access to a file/folder caused an exception. So what you need to do is to catch the exception which indicate file/folder access violations

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml;
using System.Xml.Linq;
using System.IO;

namespace WriteFileNamesXml
{
    class Program
    {
        const string FILENAME = @"c:\temp\test.xml";
        const string FOLDER = @"c:\temp";
        static XmlWriter writer = null;
        static void Main(string[] args)
        {
            XmlWriterSettings settings = new XmlWriterSettings();
            settings.Indent = true;

            writer = XmlWriter.Create(FILENAME, settings);
            writer.WriteStartDocument(true);

            DirectoryInfo info = new DirectoryInfo(FOLDER);
            WriteTree(info);

            writer.WriteEndDocument();
            writer.Flush();
            writer.Close();


        }
        static long WriteTree(DirectoryInfo info)
        {
            long size = 0;
            writer.WriteStartElement("Folder");
            try
            {
                writer.WriteAttributeString("name", info.Name);
                writer.WriteAttributeString("numberSubFolders", info.GetDirectories().Count().ToString());
                writer.WriteAttributeString("numberFiles", info.GetFiles().Count().ToString());
                writer.WriteAttributeString("date", info.LastWriteTime.ToString());


                foreach (DirectoryInfo childInfo in info.GetDirectories())
                {
                    size += WriteTree(childInfo);
                }

            }
            catch (Exception ex)
            {
                string errorMsg = string.Format("Exception Folder : {0}, Error : {1}", info.FullName, ex.Message);
                Console.WriteLine(errorMsg);
                writer.WriteElementString("Error", errorMsg);
            }

            FileInfo[] fileInfo = null;
            try
            {
                fileInfo = info.GetFiles();
            }
            catch (Exception ex)
            {
                string errorMsg = string.Format("Exception FileInfo : {0}, Error : {1}", info.FullName, ex.Message);
                Console.WriteLine(errorMsg);
                writer.WriteElementString("Error", errorMsg);
            }

            if (fileInfo != null)
            {
                foreach (FileInfo finfo in fileInfo)
                {
                    try
                    {
                        writer.WriteStartElement("File");
                        writer.WriteAttributeString("name", finfo.Name);
                        writer.WriteAttributeString("size", finfo.Length.ToString());
                        writer.WriteAttributeString("date", info.LastWriteTime.ToString());
                        writer.WriteEndElement();
                        size += finfo.Length;
                    }
                    catch (Exception ex)
                    {
                        string errorMsg = string.Format("Exception File : {0}, Error : {1}", finfo.FullName, ex.Message);
                        Console.WriteLine(errorMsg);
                        writer.WriteElementString("Error", errorMsg);
                    }
                }
            }

            writer.WriteElementString("size", size.ToString());
            writer.WriteEndElement();
            return size;

        }
    }
}