title: Date type in Powershell ConvertTo-JSON
body: <p>In Powershell, if I obtain DHCP leases from a server using <code>Get-DHCPServerv4Lease</code> and then convert that to JSON, here is an example output:</p>
  
  <pre><code>....
  "LeaseExpiryTime" : "\/Date(1457009853298)\/",
  ....
  </code></pre>
  
  <p><strong>My question: What is that date number?</strong> Its not Unix timestamp or Windows filetime.</p>
  
  <pre><code>Unix TS:          Thursday, October 20, 48140 11:14:58pm
  Windows Filetime: Tuesday, January 2, 1601 4:28:21pm
  </code></pre>
  
  <p>The lease expiry time in the DHCP console is <code>3/3/2016 7:57:33 AM EST</code>. The best I've been able to come up with is chopping off the last three digits, which turns it into a proper Unix timestamp and gives me the correct time in UTC (my TZ is EST).</p>
  
  <p>Of course, if I <code>ConvertFrom-Json</code> I get a proper <code>DateTime</code> object, albeit in UTC rather than EST:</p>
  
  <pre><code>$data | ConvertFrom-JSON
  ....
  LeaseExpiryTime : 3/3/2016 12:57:33 PM
  </code></pre>
  
  <p>I can't seem to make a correct date using <code>Get-Date</code> or even any methods in <code>[DateTime]::</code> using that '1457009853298'</p>
  
  <p>Running <code>Get-Date | Convertto-JSON</code> gives me the below, but I still don't know what I can do with that value.</p>
  
  <pre><code>{
  "value":  "\/Date(1456939716572)\/",
  "DisplayHint":  2,
  "DateTime":  "Wednesday, March 2, 2016 12:28:36 PM"
  }
  </code></pre>