User`s guide

292 VEE User’s Guide
7 Using .NET with VEE
VEE and Primary Interop Assemblies
When you choose the COM tab in Device ⇒ .NET Assembly
References, VEE goes through the registry and finds all
registered COM type libraries on your machine. As you select
COM type libraries, if the library has a PIA and the
PrimaryInteropAssemblyCodeBase key for the COM type
library is registered, then the PIA location is shown in the
Function & Object Browser description area. Note that
PrimaryInteropAssemblyCodeBase is only registered when
the PIA is registered with /codebase option. Not all PIAs are
registered this way. Currently, all Agilent IVI- COM drivers
are registered with the /codebase option, but many
assemblies are not. Also note that when you check a COM
type library, all VEE does is look at the registry, it does not
load the interop assembly if there is one. Once you choose
OK, if there is no PIA, then VEE will generate one or more
Interop Assemblies automatically. The Interop Assemblies are
also loaded after the OK button is clicked.
If you choose Browse and select a PIA or an Interop
Assembly directly, however, VEE actually loads the interop
assembly in order to find out which COM type library it
belongs to and whether it is a primary interop assembly or
not, which is the key difference between browse/select and
just a check on the COM tab list. After the interop assembly
is loaded, VEE finds out which COM type library it belongs
to and then checkmarks the corresponding COM type
libraries under the COM tab list.