You will need to reference the following:
C:\Program Files\Accelerator for .NET\vM_M\Core\DotNet\A4DN.Core.BOS.DataController.dll
C:\Program Files\Accelerator for .NET\ vM_M\Core\DotNet\BOS.AcceleratorMaintenanceEntities.dll
You will need to add this using statement:
using BOS.UsersDataEntity;
Then you can cast the ap_UserEntity to get all the properties..
var ue = AB_DataPropertyController.ap_UserEntity as UsersEntity;