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  1. PO
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    <p>I understand it's <code>MoveNext</code> that throws the exception. </p> <p>I tried to write a method that safe-walks a sequence and tries to ignore <code>MoveNext</code> exceptions. However I'm not sure if <code>MoveNext</code> advances position when it throws an exception, so this might as well be infinite loop. It is also bad idea because we would rely on implementation details.</p> <p>But it's just <strong>so much fun!</strong></p> <pre><code>public static IEnumerable&lt;T&gt; SafeWalk&lt;T&gt; (this IEnumerable&lt;T&gt; source) { var enumerator = source.GetEnumerator(); bool? hasCurrent = null; do { try { hasCurrent = enumerator.MoveNext(); } catch { hasCurrent = null; // we're not sure } if (hasCurrent ?? false) // if not sure, do not return value yield return enumerator.Current; } while (hasCurrent ?? true); // if not sure, continue walking } foreach (var file in Directory.EnumerateFiles("c:\\", "*", SearchOption.AllDirectories) .SafeWalk()) { // ... } </code></pre> <p>This will only work if the following conditions are true about framework's implementation of this iterator (see <code>FileSystemEnumerableIterator&lt;TSource&gt;</code> in Reflector for reference):</p> <ul> <li><code>MoveNext</code> advances its position when it fails;</li> <li>When <code>MoveNext</code> fails on last element, subsequent calls will return <code>false</code> instead of throwing an exception;</li> <li>This behavior is consistent for different versions of .NET Framework;</li> <li>I haven't made any logic or syntax mistakes.</li> </ul> <p>Even if it works, please, never use it in production!<br> But I really wonder if it does.</p>
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    1. PODirectory.EnumerateFiles => UnauthorizedAccessException
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    1. USDan Abramov
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      1. VTUpMod
    1. CONot bad, but it wohn't work for my scenario: I need it to continue and move on when it meets an exception: the only difference between a safe-walk and a normal walk is that the safe-walk just stops enumeration whilst the normal method stops with an exception. I need it to continue and ignore any exceptions in the sense that it should enumerate all directories it can and just skip the ones it doesn't have access to. That, unfortunately it appears, requires a new implementation of the BCL implementation.
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      1. USBent Rasmussen
    2. CO...I would have no issue using it in production if it worked ;-) ... but even then it would need a few modifications: for example you don't want to catch *all* exceptions, it should just be UnauthorizedAccessException or at least it should be filterable via a lambda.
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