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Property Node

LabVIEW 8.2 Help
August 2006

NI Part Number:
371361B-01

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Gets (reads) and/or sets (writes) properties of a reference. The Property Node automatically adapts to the class of the object that you reference. LabVIEW includes Property Nodes preconfigured to access VISA properties, .NET properties, and ActiveX properties. Details  

reference is the refnum associated with the object for which you want to set or get properties. If the Property Node class is Application or VI, you do not have to wire a refnum to this input. For the Application class, the default is the current application instance. For the VI class, the default is the VI containing the Property Node.
error in describes error conditions that occur before this VI or function runs. The default is no error. If an error occurred before this VI or function runs, the VI or function passes the error in value to error out. This VI or function runs normally only if no error occurred before this VI or function runs. If an error occurs while this VI or function runs, it runs normally and sets its own error status in error out. Use the Simple Error Handler or General Error Handler VIs to display the description of the error code. Use error in and error out to check errors and to specify execution order by wiring error out from one node to error in of the next node.
status is TRUE (X) if an error occurred before this VI or function ran or FALSE (checkmark) to indicate a warning or that no error occurred before this VI or function ran. The default is FALSE.
code is the error or warning code. The default is 0. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code.
source specifies the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning. The default is an empty string.
property 2..n are examples of properties you want to set (write).
reference out returns reference unchanged.
error out contains error information. If error in indicates that an error occurred before this VI or function ran, error out contains the same error information. Otherwise, it describes the error status that this VI or function produces. Right-click the error out front panel indicator and select Explain Error from the shortcut menu for more information about the error.
status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred.
code is the error or warning code. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code.
source describes the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning.
property 1..n are examples of properties you want to get (read).

Property Node Details

To select the class on which to execute the property, wire the refnum to the reference input. For example, to select the VI, Generic, or Application class, wire the VI, VI object, or application refnum to the reference input. The node adapts to the class automatically. You also can right-click the node and select a class from the shortcut menu.

Move the cursor over terminals in the Property Node to display more information about the property in the Context Help window. You also can right-click a property terminal and select Help For Property from the shortcut menu, where Property is the name of the property.

To get property information, right-click the node and select Change All to Read from the shortcut menu. To set property information, right-click the node and select Change All to Write from the shortcut menu. If a property is read only, Change to Write is dimmed in the shortcut menu.

The node executes each terminal in order from top to bottom. If an error occurs on a terminal, the node stops at that terminal, returns an error, and does not execute any further terminals. You can right-click the node and select Ignore Errors Inside Node from the shortcut menu to ignore any errors and continue executing further terminals. If an error occurs when Ignore Errors Inside Node is set, the property node still returns that error. The error out cluster reports which property caused the error.

If the small direction arrow on the property is on the right, you are getting the property value. If the small direction arrow on a property is on the left, you are setting the property value. Properties have a short or long name that you can change by right-clicking and selecting Name Format from the shortcut menu. The No Names format displays only the data type for each property.

ActiveX Property Node (Windows)

If the property you want to write is variant, you can wire in LabVIEW data types and they automatically convert to variant data types indicated by a coercion dot. ActiveX does not support 64-bit integer data types. If you wire a 64-bit integer data type to a variant parameter of an ActiveX Property Node, LabVIEW converts the data type to a double-precision, floating-point number. If the property is variant, use the Variant To Data function to convert to a LabVIEW data type, if needed. If you right-click the Property Node and select Select Class»ActiveX»Browse from the shortcut menu, LabVIEW displays the Select Object From Type Library dialog box.

On the front panel or block diagram, right-click an ActiveX object, select Create»Property Node, and select a property from the shortcut menu to set a property for the object. You also can select ActiveX-specific properties for an ActiveX object. On the block diagram, right-click an ActiveX object, select Create»Property Node, and select an ActiveX-specific property from the shortcut menu.

.NET Property Node (Windows)

If you right-click the Property Node and select Select Class».NET»Browse from the shortcut menu, LabVIEW displays the Select Object From Assembly dialog box.

On the front panel or block diagram, right-click a .NET object, select Create»Property Node, and select a property from the shortcut menu to set a property for the object. You also can select .NET-specific properties for a .NET object. On the block diagram, right-click a .NET object, select Create»Property Node, and select a .NET-specific property from the shortcut menu.


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