Convert Windows FILTIME value to .NET DateTime
<p>We have a database from third party software where it has LastModifiedDate field stored as WINDOWS filetime. 
We need to conver this to .NET DateTime format and supricingly it has -ve values. </p>

<p>.NET's DateTime.FromFileTimeUtc method will work for +ve filetime values btu for -ve values it will not work. </p>

<p>How do i convert -ve filttime value to DateTime format ?
Sample valules:
-ve value : -9094325347534722713
+ve value : 8872694038044633872</p>
