Application Control VIs and Functions

Owning Palette: Programming VIs and Functions

Requires: Base Development System. This topic might not match its corresponding palette in LabVIEW depending on your operating system, licensed product(s), and target.

Use the Application Control VIs and functions to programmatically control VIs and LabVIEW applications on the local computer or across a network. You can use these VIs and functions to configure multiple VIs at the same time.

Palette ObjectDescription
Call By ReferenceCalls the VI specified by reference. The reference VI must be a strictly typed VI reference.
Call ChainReturns the chain of callers from the current VI to the top-level VI. Element 0 of the call chain array contains the name of the lowest VI in the call chain. Subsequent elements are callers of the lower VIs in the call chain. The last element of the call chain array is the name of the top-level VI.
Class Specifier ConstantSelects the class of the output.

You also can create a class specifier constant from a control refnum control or terminal.
Close ReferenceCloses a refnum associated with an open VI, VI object, an open application instance, or a .NET or ActiveX object.
Get Command Line ArgumentsReturns the arguments passed from the command line when LabVIEW or a LabVIEW-built application launched. User-defined arguments start after two hyphens (--) surrounded by spaces in the command line.

If an argument contains double quotation marks ("), this VI returns the argument without the quotation marks.
Get Control Values by IndexGets values from the controls for the VI you reference. This function offers better performance than VI Server objects that read from the terminal of a front panel control, such as using the Value property in the Control class. However, this function requires more advanced application design than other methods for getting control values.
Get Drag Drop DataReturns drag data from the current drag and drop operation. Only use this function when it is necessary to access the drag data, not just to examine the data type. If a drag and drop operation is not in progress, LabVIEW returns an error. If the data requested is unavailable, LabVIEW returns an error.
Invoke NodeInvokes a method or action on a reference. Most methods have associated parameters.
Open Application ReferenceReturns a reference to a VI Server application running on the specified computer.
Open VI ReferenceReturns a reference to a VI, custom control, or global variable specified by a name string or path to the VI location on disk.
Property NodeGets (reads) and/or sets (writes) properties of a reference. Use the property node to get or set properties and methods on local or remote application instances, VIs, and objects. You also can use the Property Node to access the private data of a LabVIEW class.
Quit LabVIEWStops all executing VIs and ends the current instance of LabVIEW.
Set Control Values by IndexSets values to the controls for the VI you reference. This function offers better performance than VI Server objects that write to the terminal of a front panel control, such as using the Value property in the Control class. However, this function requires more advanced application design than other methods for setting control values.
Start Asynchronous CallStarts an asynchronous call to the VI indicated by the reference input. Depending on how you prepare reference for asynchronous execution with the Open VI Reference function, you can either ignore the VI after calling it or collect its outputs at a later time with the Wait On Asynchronous Call node.
Static VI ReferenceMaintains a static reference to a VI. You can configure the Static VI Reference function to output a generic or strictly typed VI reference. After you place the Static VI Reference function on a block diagram, double-click the function to display a file dialog box where you can select a VI.
StopStops the VI in which it executes, just as if you clicked the Abort Execution button on the toolbar. Before you call this function with a TRUE input, be sure to complete all final tasks for the VI first, such as closing files, setting safe values for devices being controlled, and so on.
To More Generic ClassTypecasts a reference, such as a control or a type definition, to a more generic class or interface in the inheritance hierarchy.
To More Specific ClassTypecasts a reference, such as a control or a type definition, to a more specific class or interface in the inheritance hierarchy.
VI Server ReferenceReturns a static VI reference to the current VI by default. You can reconfigure this reference to return a reference to the current application, to a control or indicator in the VI, or to a pane by clicking on the block diagram icon and choosing from the shortcut menu. You can use this reference to access the properties and methods for the associated VI, application, control, indicator, or pane. The VI Server Reference always returns a fully authenticated reference. Use caution when passing references to other VIs if you are concerned about password security.
Wait On Asynchronous CallWaits for an asynchronous call to a target VI to finish executing and then returns the outputs of the target VI. To use the Wait On Asynchronous Call node on a reference, you must include the 0x100 option flag as part of the options input of the Open VI Reference function when you open the reference. You also must call the target VI with the Start Asynchronous Call node.


SubpaletteDescription
Application Builder VIsUse the Application Builder VIs to build, deploy, or clean build specifications.
CPU Information FunctionsUse the CPU Information functions to obtain information on the characteristics of a computer or target.
Memory Control VIs and FunctionsUse the Memory Control VIs and functions to improve LabVIEW memory performance.
Palette Editing VIsYou can use the Palette Editing VIs to edit the Controls or Functions palette set programmatically.
VI Scripting VI and FunctionsYou can use the VI Scripting VI and functions to create, edit, and run VIs programmatically.