Got my self all balled up with this one:

Correct:

<xmod:EditLink Text="Edit">
<Parameter Name="Class_Id" Value='[[Class_Id]]' />
</xmod:EditLink>

Incorrect:

<xmod:EditLink Text="Edit">
<Parameter Name="Class_Id" Value="[[Class_Id]]" />
</xmod:EditLink>

When using Quotes, the proper Value parameter is not passed to the Edit form, but with Apostrophes it works fine.