You are here: NI Home > Support > Product Reference > Manuals > LabVIEW 8.5 Help

Use Property Nodes to get and set VI, object, or application properties. Use Invoke Nodes to perform actions, or methods, on a VI, object, or application.

You can create multiple Property Nodes and Invoke Nodes for the same front panel object.

You can use the Class Browser window to browse for and create Property Nodes and Invoke Nodes, or you can complete the following steps to create a Property Node or Invoke Node.

Complete the following steps to create a Property Node or Invoke Node.

1. Determine if you want to create a Property Node or Invoke Node for the Application class, the VI class, or a front panel object.
   • Place one of the following nodes on the block diagram. You must wire a refnum for the front panel object to the reference terminal of the node.
     • Property Node
       
       
     • Invoke Node
       
       
   • You also can right-click a front panel object or its block diagram terminal, select Create»Property Node or Create»Invoke Node from the shortcut menu, and select a property or method from the list to create a Property Node or Invoke Node implicitly linked to the object. If the object has a label, the Property Node has the same label. You can change the label after you create the node. If you select a method, the associated parameters appear in the node.
     
     (Windows) To create a .NET Property Node or Invoke Node, wire a .NET container or a .NET reference to the reference terminal of the node. To create an ActiveX Property Node or Invoke Node, wire an ActiveX container or automation refnum to the reference terminal of the node.
2. Right-click the node and select Select Class from the shortcut menu to specify a class for the node.
3. If you are creating a Property Node or Invoke Node for the Application or VI classes of VI Server and you do not want to use the current VI or application, complete the following steps.
   1. Place one of the following functions on the block diagram:
      • Open Application Reference
        
        
      • Open VI Reference
        
        
   2. Wire the application reference output of the Open Application Reference function or the vi reference output of the Open VI Reference function to the reference input of the Property Node or Invoke Node. If you do not wire a refnum to the reference input, the Property Node or Invoke Node uses a reference to the current application instance or a reference to the VI containing the Property Node or Invoke Node.
4. To add terminals to the Property Node, right-click the white area of the node and select Add Element from the shortcut menu or use the Positioning tool to resize the node.
5. If the Property Node returns a reference or an array of references to an object, use the Close Reference function to close the reference.

Note  If you place the Property Node in a While Loop or For Loop and the Property Node returns a reference to an object, you must close that reference for each iteration of the loop. You can move the Property Node outside the loop and close the reference after all iterations of the loop execute.