ActiveX Features Supported in LabVIEW

Updated May 3, 2018

Reported In

Software

  • LabVIEW Full
  • LabVIEW Base
  • LabVIEW Professional

Issue Details

I want to use ActiveX in LabVIEW but I don't know which features LabVIEW supports

Solution

ActiveX is a set of Microsoft technologies based on the Microsoft Component Object Model (COM) used for interapplication communication. Common ActiveX technologies are:
  • ActiveX Control - Interactive objects, such as component controls or a calendar control, that can be used in containers such as a Web browser.
  • ActiveX Documents - Enables users to view documents, such as Microsoft Word documents or Microsoft Excel spreadsheets, in an ActiveX container, such as a CVI panel.
  • ActiveX Automation - Control one application from within another application.

Additional Information

ActiveX Applications can either be an ActiveX server or an ActiveX client. ActiveX servers export an Application Programming Interface (API) or a set of properties and methods to other applications. ActiveX clients get or set properties and invoke methods of a server and thus can control the behavior of the ActiveX server.

There are two types of ActiveX references available in LabVIEW: Automation Servers and ActiveX Controls. An Automation Server is a DLL that has been explicitly registered with the system to be controlled through ActiveX. An example of an ActiveX server is Microsoft Word. You can use ActiveX automation to launch Word, open a document, and close the application. 

Every ActiveX server "exposes" certain properties and methods to an ActiveX client like LabVIEW which is controlling the server. In the case of Word, an example of a property is the font of some body of text. Performing a spelling check is an example of a method. 

To use ActiveX Server Automation, you should first open a reference to the server with the Automation Open VI. You can control methods and properties using Invoke Nodes and Property Nodes respectively. Once all operations are complete, an Automation Close VI should be used to release the computer resources associated with the connection. 

In addition to ActiveX Automation described above, LabVIEW also allows you include ActiveX Controls in your application. This is a file with a .ocx extension that has been registered as an ActiveX control. These controls must be placed inside an ActiveX container on the Front Panel. Then the refnum (reference number) from the terminal on the block diagram can be directly wired into the Invoke and Property nodes to access the control. 

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