How can I get whether directory accessible without try&catch?

Question

Now I am about to get directories of "C:\Documents and Settings" like this:

var d=Directory.GetDirectories(@"C:\Documents and Settings")

Visual Studio reports an error:

System.UnauthorizedAccessException: 'Access to the path 'C:\Documents and Settings' is denied.'

Well, the directory is inaccessible.

I want to get to know whether the directory about to get is accessible.

Many tutorials, just like this:https://stackoverflow.com/questions/172544/ignore-folders-files-when-directory-getfiles-is-denied-access , are using a try&catch to avoid the error.

As we know, try&catch will slow down the speed. And also, I don't think it is the best way.

Is there any way to solve this? Thank you.

Trying to access a folder and being denied is not a trivial situation. It warrants a try-catch in my opinion. — Nyerguds, Sep 14 '20 at 11:17
It's possible in .NET Core, not possible in .NET Old. Now that .NET (Core) 5 replaces .NET Old, you can use the `EnumerationOptions` parameter to skip inaccessible entries — Panagiotis Kanavos, Sep 14 '20 at 11:17
A try/catch is fine for a solution unless you have a high number of checks like in a loop using recursion and you are worried about execution time for example. — Igor, Sep 14 '20 at 11:17
@PanagiotisKanavos Yeah! I am using the .net 5 now. Would you please tell me more about this? — Melon NG, Sep 14 '20 at 11:22
@PanagiotisKanavos I marked it as the right answer just now. Thank you. — Melon NG, Sep 14 '20 at 11:29

score 3 · Accepted Answer · answered Sep 14 '20 at 11:21

This is possible in .NET Core with the GetDirectories, GetFiles, EnumerateDirectories and EnumerateFiles overloads that accept the EnumerationOptions parameter:

var options = new EnumerationOptions { IgnoreInaccessible=true };
var files=Directory.GetDirectories(somePath,"*",options);

EnumerationOptions exists only in .NET Core 2.1 and later, or .NET Standard 2.1 or later. To use it with Windows Forms or WPF applications you'll have to migrate them to .NET (Core) 5 first.

score 0 · Answer 2 · answered Sep 14 '20 at 11:16

0

I think Directory.Exists() should do the trick. According to the Remarks it will return false if the directory is not accessible.

answered Sep 14 '20 at 11:16

MultiValidation

823
7
21

It won't - how will the code know what the file's name ? – Panagiotis Kanavos Sep 14 '20 at 11:17
1

`Directory.Exists()` uses a plethora of catch blocks :) Well, yes, you cannot see them... You could check [FileIOPermission](https://learn.microsoft.com/en-us/dotnet/api/system.security.permissions.fileiopermission), which is used internally. – Jimi Sep 14 '20 at 11:19

How can I get whether directory accessible without try&catch?

2 Answers2