What is the fastest way to calculate a Windows folders size?

Question

I need to calculate the size of hundreds of folders, some will be 10MB some maybe 10GB, I need a super fast way of getting the size of each folder using C#.

My end result will hopefully be:

Folder1 10.5GB

Folder2 230MB

Folder3 1.2GB

...

Answer 1

Add a reference to the Microsoft Scripting Runtime and use:

Scripting.FileSystemObject fso = new Scripting.FileSystemObject();
Scripting.Folder folder = fso.GetFolder([folder path]);
Int64 dirSize = (Int64)folder.Size;

If you just need the size, this is much faster than recursing.

Answer 2

OK, this is terrible, but...

Use a recursive dos batch file called dirsize.bat:

@ECHO OFF
IF %1x==x GOTO start
IF %1x==DODIRx GOTO dodir
SET CURDIR=%1
FOR /F "usebackq delims=" %%A IN (`%0 DODIR`) DO SET ANSWER=%%A %CURDIR%
ECHO %ANSWER%
GOTO end
:start
FOR /D %%D IN (*.*) DO CALL %0 "%%D"
GOTO end
:dodir
DIR /S/-C %CURDIR% | FIND "File(s)"
GOTO end
:end

Note: There should be a tab character after the final "%%A" on line 5, not spaces.

This is the data you're looking for. It will do thousands of files fairly quickly. In fact, it does my entire harddrive in less than 2 seconds.

Execute the file like this dirsize | sort /R /+25 in order to see the largest directory listed first.

Good luck.