In 14 SDF I used to be able to work out the amount of free space using the following two statements.
OpenNETCF.IO.StorageCard.GetDiskFreeSpace("SD Card").TotalFreeBytes
OpenNETCF.IO.StorageCard.GetDiskFreeSpace("SD Card").TotalBytes
I can see that in 2.2 the Namespace has changed to: OpenNETCF.IO.DriveInfo but I can't work out to use the new class to get the Total and available bytes from a names device like 'SD Card'.