Directory.GetFiles - different output dependent on OS
.net, .net-4.5, c#, visual-studio, visual-studio-2013
Solution
Your Windows 7 behavior is by design. From the documentation on the GetFiles() method (see the first note below the "Remarks" section):
When using the asterisk wildcard character in a searchPattern, such as "*.txt", the matching behavior when the extension is exactly three characters long is different than when the extension is more or less than three characters long. A searchPattern with a file extension of exactly three characters returns files having an extension of three or more characters, where the first three characters match the file extension specified in the searchPattern. A searchPattern with a file extension of one, two, or more than three characters returns only files having extensions of exactly that length that match the file extension specified in the searchPattern.
The Windows 8.1 behavior is a not reproducible for me. I just ran a test on my Windows 8.1 x64 machine, and it matched the expected Windows 7 behavior. I would check that the current folder on the machine is correct.
I can also get the same results just by opening up a command prompt, navigating to the appropriate directory, and typing `dir *.xls`. I expect that both the GetFiles() function and the command prompt will pass the search pattern into the same low-level operating system function.
It's talking about some different issues, but this post is also worth a read:
http://blogs.msdn.com/b/oldnewthing/archive/2007/12/17/6785519.aspx
Problem
I have a simple program. It runs .NET 4.5 and is built in Visual Studio 2013. `D:\\MyDir` is full of `.xlsx` files and no `.xls` files. When I run the program on Windows 8.1 x64, the filter for `*.xls` returns no results. When I run the same program, with the same .NET version on Windows 7 x86, the `*.xls` filter returns the same results as the `*.xlsx` filter. The test folders on both systems definitely contain the same data. Am I missing something, or is this a bug in .NET and/or Windows? The respective code: ``` using System; using System.Collections.Generic; using System.IO; using System.Linq; using System.Text; using System.Threading; using System.Threading.Tasks; namespace throw_test { static class Program { static void Main() { int fileCount1 = Directory.GetFiles("D:\\MyDir", "*.xlsx").Length; int fileCount2 = Directory.GetFiles("D:\\MyDir", "*.xls").Length; Console.WriteLine("File Count 1: " + fileCount1); Console.WriteLine("File Count 2: " + fileCount2); Console.Read(); } } } ``` Edit 1 When I navigate to the directory using the command prompt in Windows 8.1 x64: - `dir *.xlsx` returns all files as expected - `dir *.xls` returns 'File Not Found' Windows 7 returns the expected files on both of the above commands. My guess is that .NET uses this command under the hood, thus the above results?