Check if directory is accessible in C#? [duplicate]

Answer 1

I think you are looking for the GetAccessControl method, the System.IO.File.GetAccessControl method returns a FileSecurity object that encapsulates the access control for a file.

Answer 2

According to MSDN, Directory.Exists should return false if you don't have read access to the directory. However, you can use Directory.GetAccessControl for this. Example:

public static bool CanRead(string path)
{
    try
    {
        var readAllow = false;
        var readDeny = false;
        var accessControlList = Directory.GetAccessControl(path);
        if(accessControlList == null)
            return false;

        //get the access rules that pertain to a valid SID/NTAccount.
        var accessRules = accessControlList.GetAccessRules(true, true, typeof(System.Security.Principal.SecurityIdentifier));
        if(accessRules ==null)
           return false;

        //we want to go over these rules to ensure a valid SID has access
        foreach (FileSystemAccessRule rule in accessRules)
        {
            if ((FileSystemRights.Read & rule.FileSystemRights) != FileSystemRights.Read) continue;

            if (rule.AccessControlType == AccessControlType.Allow)
                readAllow = true;
            else if (rule.AccessControlType == AccessControlType.Deny)
                readDeny = true;
        }

        return readAllow && !readDeny;
    }
    catch(UnauthorizedAccessException ex)
    {
        return false;
    }
}

Update

As mentioned in some comments, this may return an incorrect value in a case where a valid SID in an external DOMAIN has access. In order to check if the current user has access, you need something like:

foreach...

if (WindowsIdentity.GetCurrent().User.Value.equals(rule.IdentityReference.Value))

This will confirm if the SID of the current user matches the access rule identity reference but may throw a SecurityException as well.