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POLosing type information when passing an object through a System.Collections.Queue
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  1. POLosing type information when passing an object through a System.Collections.Queue
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    copied!<p>As part of my Powershell script I need to, essentially, implement breadth-first search. So, I need queue and figured System.Collections.Queue is as good as any other queue. However, when I get an object out of the queue, Powershell loses track of any properties I've added to the object.</p> <p>What's going on here? How do I access my property?</p> <p>This sample demonstrates the problem:</p> <pre><code>$object = new-object object add-member -membertype noteproperty -name AnInteger -value 2 -inputobject $object $queue = new-object system.collections.queue $queue.enqueue($object) $dequeued = $queue.dequeue() # 1. True - both variables refer to the same object. $object -eq $dequeued # 2. True - using the original variable, can access the property. $object.AnInteger -ne $null # 3. False. Err, What? $dequeued.AnInteger -ne $null </code></pre> <h1>Solution and More Questions</h1> <p>I found my mistake: <code>add-member</code> modifies an instance of <code>PSObject</code> not Object. It looks like it created one for me to wrap <code>$object</code> before adding the property. So, I needed to either create a <code>PSObject</code> or cast the result of dequeue to <code>PSObject</code>. </p> <p>I still don't understand everything that's going on here. Did <code>add-member</code> modify <code>$object</code> to refer to the <code>PSObject</code> it created? If not, how did the Powershell run-time know that <code>$object</code> was in fact a <code>PSObject</code>? <code>$object.gettype().name</code> is <code>Object</code> not <code>PSCustomObject</code>.</p>
 

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