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Chapter 2 New Features in LabVIEW 5.1
LabVIEW 5.1 Addendum 2-12
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National Instruments Corporation
IVI Instrument Drivers and ActiveX
Some parameters for ActiveX and IVI take a discrete list of valid values.
Previously, when building ActiveX and IVI applications, you used numeric
values to set parameters for properties and methods that control devices or
programs. You had to enter a particular numeric value in a numeric control
or constant, which required you to know which numeric values
corresponded to which settings.
With LabVIEW 5.1, you are not required to know these values. You can
choose from a descriptive name in a ring to set parameter values. The
selections available in the ring depend on the refnum passed to the node.
See Figure 2-3 and Figure 2-4 below for examples of using these numeric
and ring constants.
Figure 2-3.
Setting a Data Value with a Numeric Constant
Figure 2-4.
Setting a Data Value with a Ring Constant
In both examples, the Microsoft Excel application is accessed and a method
is invoked. The Index parameter has several options: MicrosoftAccess,
MicrosoftFoxPro, MicrosoftMail, MicrosoftPowerPoint, MicrosoftProject,
MicrosoftSchedulePlus, and MicrosoftWord.
Previously you were required to know that the Index parameter
corresponding to the MicrosoftAccess option is the data value 4. Now you
can select the Microsoft Access option from the drop-down menu in the ring
constant.