Accessing alternative data-streams of files on an NTFS volume

• For compound files, such as Office documents, the summary information is stored in the file.
  
  
  
  • Office 2007 files can be manipulated with the OpenXML SDK[^];
  
  
  • For older file versions, you need to use the DSOFile[^] component;
  
  



• In Vista, most of the summary information is stored within the file; this is why the available fields varies depending on the file type.



• In older versions of Windows, the information is stored in an alternate data stream, and can be manipulated via the IPropertySetStorage[^] interface.

using System;
using System.IO;
using Trinet.Core.IO.Ntfs;

static class Program
{
    static void Main()
    {
        try
        {
            string fileName = Path.GetFullPath("Your File Path Here");
            if (!File.Exists(fileName))
            {
                Console.WriteLine("Test file not found.");
            }
            else
            {
                WriteTestStream(fileName);
                ReadTestStream(fileName);
            }
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex);
        }
    }
    
    static void WriteTestStream(string fileName)
    {
        var info = FileSystem.GetAlternateDataStream(fileName, "Test");
        
        using (var fileStream = info.OpenWrite())
        using (var writer = new StreamWriter(fileStream))
        {
            writer.Write("hello ADS");
        }
    }
    
    static void ReadTestStream(string fileName)
    {
        var info = FileSystem.GetAlternateDataStream(fileName, "Test");
        
        if (info.Exists)
        {
            Console.WriteLine("Alternate data stream found:");
            using (var reader = info.OpenText())
            {
                Console.WriteLine(reader.ReadToEnd());
            }
        }
        else
        {
            Console.WriteLine("Alternate data stream not found: {0}", info);
        }
    }
}

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using Trinet.Core.IO.Ntfs;

static class Program
{
    static void Main()
    {
        try
        {
            TestStream(new FileInfo("test.jpg"));
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex);
        }
    }
    
    static void TestStream(FileInfo file)
    {
        var streams = file.ListAlternateDataStreams();
        if (0 == streams.Count)
        {
            Console.WriteLine("No streams found.");
        }
        else
        {
            Console.WriteLine("Found {0} stream(s):", streams.Count);
            foreach (var item in streams)
            {
                Console.WriteLine(item.Name);
            }
            Console.WriteLine();
        }
        
        const string ThumbnailStreamName = "thumb";
        
        if (file.AlternateDataStreamExists(ThumbnailStreamName))
        {
            Console.WriteLine("Thumbnail stream exists:");
            using (var stream = file.GetAlternateDataStream(ThumbnailStreamName).OpenRead())
            using (var thumbnail = Image.FromStream(stream))
            {
                Console.WriteLine("Read thumbnail - size {0}x{1}", thumbnail.Width, thumbnail.Height);
            }
            
            file.DeleteAlternateDataStream(ThumbnailStreamName);
        }
        else
        {
            Console.WriteLine("Creating thumbnail:");
            
            using (var inputStream = file.OpenRead())
            using (var inputImage = Image.FromStream(inputStream))
            {
                int targetWidth = 100;
                int targetHeight = 100;
                
                int w = (int)(inputImage.Width * targetHeight / inputImage.Height);
                int h = (int)(inputImage.Height * targetWidth / inputImage.Width);
                if (w > targetWidth)
                {
                    targetHeight = h;
                }
                else if (h > targetHeight)
                {
                    targetWidth = w;
                }
                
                using (var thumbnail = inputImage.GetThumbnailImage(targetWidth, targetHeight, null, IntPtr.Zero))
                using (var outputStream = file.GetAlternateDataStream(ThumbnailStreamName).OpenWrite())
                {
                    thumbnail.Save(outputStream, ImageFormat.Jpeg);
                    Console.WriteLine("Created thumbnail: Size {0}x{1}", thumbnail.Width, thumbnail.Height);
                }
            }
        }
    }
}

...>TestStreams
No streams found.
Creating thumbnail:
Created thumbnail: Size 100x74

...>TestStreams
Found 1 stream(s):
thumb
Thumbnail stream exists:
Read thumbnail - size 100x74

catch (Exception ex)
{
    Console.WriteLine("Error opening stream {0}:\n{1}", _name, ex);
    return null;
}