File.Exists yields false, but the file exists

Question

I have a strange issue using File.Exists in C#, reproducable on several PC's. I see it as an error in the .NET 4 library.

I use 7ZIP and automate it from a C# program, I call CreateProcess and zip and unzip files with it. For that, I need to find out if and where 7ZIP is installed, because I don't want to depend on PATH variables.

So this is part of the code:

if (File.Exists(Environment.GetFolderPath(Environment.SpecialFolder.ProgramFiles) + "\\7-Zip\\7z.exe"))
    clsGlobal.gstr_ZIP_PROG_MIT_PFAD = "\"" + Environment.GetFolderPath(Environment.SpecialFolder.ProgramFiles) + "\\7-Zip\\7z.exe\"";

else if (File.Exists("\"C:\\Program Files (x86)\\7-Zip\\7z.exe\""))
    clsGlobal.gstr_ZIP_PROG_MIT_PFAD = "\"C:\\Program Files (x86)\\7-Zip\\7z.exe\"";

All Exist-Checks give me "false" back. The ProgramFiles-SpecialFolder points to the right (x86)-Folder, for sure. And also for sure, 7ZIP is installed in C:\Program Files (x86)\7-ZIP\7z.exe, and when calling CreateProcess, everything works fine. What can be the reason why all Exists() - Checks fail ? Is this a known bug ?

Just a thought: Please use Verbatim literal "@" to make your code readable — now he who must not be named., Sep 04 '13 at 11:13
[To expand on @nowhewhomustnotbenamed.'s comment](http://stackoverflow.com/questions/556133/whats-the-in-front-of-a-string-in-c). — Bernhard Barker, Sep 04 '13 at 11:18

score 2 · Answer 1 · answered Sep 04 '13 at 11:20

I would say that Dukeling is correct in his comment

"\"C:\\Program Files (x86)\\7-Zip\\7z.exe\""

is looking for a path starting with the double quotes BEFORE the C:\ As now he who must not be named said use the "@" before the string so it becomes:

@"C:\Program Files (x86)\7-Zip\7z.exe\"

This makes the code readable and also prevents any confusion with quotes which seems to be what is happening here.

DGibbs · Answer 2 · 2013-09-04T11:34:23.287

I see it as an error in the .NET 4 library.

This is not a bug in the .NET Framework...

Print the path value.

It will be:

C:\Program Files (x86)\7-Zip\7z.exe

By default i believe 7-Zip installs to Program Files and not Program Files (x86).

You are using:

Environment.SpecialFolder.ProgramFiles

If your code is built to target x86 (i suspect it is) then this enum will give you:

Program Files (x86)

System.EnvironmentSpecialFolder

The program files directory.On a non-x86 system, passing ProgramFiles to the GetFolderPath method returns the path for non-x86 programs. To get the x86 program files directory on a non-x86 system, use the ProgramFilesX86 member.

Which is not the folder that 7-Zip installs to.

If you change your code to read:

if (File.Exists(@"C:\Program Files\7-Zip\7z.sfx"))

You should be fine

Alternatively, target x64 and the enum will return the Program Files string:

config

The path will now read:

C:\Program Files\7-Zip\7z.exe

File.Exists yields false, but the file exists

2 Answers2