Most efficient way to find all exe files on disk using C#?

Question

What is the most efficient way to find all exe files on disk using C#?

It will be done in background thread in program so disk usage should be as small as possible.

Rudolf

What have you done so far? You can enumerate all the directories of the machine and use the overload of Directory.GetFiles that takes a file pattern (e.g. ".exe"). If it is running, you might find qurying the Windows Search database to be much faster as it will have preindexed much of this info: msdn.microsoft.com/en-us/library/windows/desktop/…. There's no guarantee the Windows Search database is up to date, so simply enumerating all of the directories and and using Directory.GetFiles might be the most accurate, at least. – Flacon

So far, msdn.microsoft.com/en-us/library/dd383458 – Rudolf

Note that the GetFiles/EnumerateFiles method is already covered here: #929776 - you can simply use a filter for exe files when searching a directory. – Flacon

similar question answered here #724648 – Respect

Answer 1

The link you provided is the most efficient way in C# (with .Net 4.0): Directory.EnumerateFiles Method

Prior versions of .Net had to use a slower method that caused memory issues on large drives, @hatchet showed a great example: Is there a faster way to scan through a directory recursively in .NET?

I wouldn't suggest using the TPL as Jon Skeet mentions here: Task Parallel Library for directory traversal

If you see the first comment in this MSDN link: Iterate File Directories with the Parallel Class I dont even think Microsoft had success with this TPL method either.

The other suggestion I have is using LogParser and you can use it with C#! Its a free Microsoft product but I'm not sure about re-dist permissions, I had to include it in my package separately last time I used it. It full on flys, faster than a speeding train!

As per @spender comment I found a Log Parser example that finds files dated 180 days and older, you could try it out and adapt it if its useful:

SELECT
    ContentPath, [Days (Old)], FileName, [Creation Date Time]
    USING creationtime AS [Creation Date Time],
    TO_DATE([Creation Date Time]) AS Cdate,
    SUB(TO_LOCALTIME(SYSTEM_TIMESTAMP()), Cdate) AS Days,
    DIV(TO_INT(Days),86400) As [Days (Old)],
    EXTRACT_PATH(TO_LOWERCASE(path)) AS ContentPath,
    TO_LOWERCASE(name) AS FileName
FROM %source% 
WHERE
  (attributes NOT LIKE 'D%')
AND
  ([Days (Old)] >= TO_INT('%day%'))
ORDER BY [Creation Date Time] DESC

%source% could be something like c:\*.exe as shown in the argument c:\temp\*.*. Save the above as cc.sql, run it with the following syntax:

 C:\Temp\Tools\Logparser>LogParser.exe file:cc.sql?source="c:\temp\*.*"+day="180"  -i:FS -preserveLastAccTime -rtp:-1

EDIT

Thanks for the upvotes guys! I made this Event Analyser app in 2005 (before .net 2.0 was released) and since the Log Parser suggestion was so popular I thought I'd share the way you can use LogParser in .Net

The good folks over at http://visuallogparser.codeplex.com/ have provided us with the source code.

Open the VisualLogParser solution in VS2010, ignore the prompt about debugging, after the solution loads, F5, set the combo-box to FS (FileSystem), paste in this query and press go.

SELECT
    ContentPath, [Days (Old)], FileName, [Creation Date Time]
    USING creationtime AS [Creation Date Time],
    TO_DATE([Creation Date Time]) AS Cdate,
    SUB(TO_LOCALTIME(SYSTEM_TIMESTAMP()), Cdate) AS Days,
    DIV(TO_INT(Days),86400) As [Days (Old)],
    EXTRACT_PATH(TO_LOWERCASE(path)) AS ContentPath,
    TO_LOWERCASE(name) AS FileName
FROM 'c:\*.exe' 
WHERE
  (attributes NOT LIKE 'D%')
AND
  ([Days (Old)] >= TO_INT('180'))
ORDER BY [Creation Date Time] DESC

At the same time you may wish run any other .Net application that searches directories and compare the results!!!

Iconology

It's not obvious how LogParser is relevant to the task of searching for .exe files. – Dekameter