Variables in a visualization project

Owned by Reinhard Mayr (Unlicensed)
Last updated: Apr 29, 2024 by Robert Schneider
3 min read

The Visualization Editor provides means to work with variables. This allows you to reuse visualization elements in a parameterized way. Variables will significantly shorten your visualization development efforts.

Basically there are two major types of a variable that differ in the point of time when the variable is substituted by a specific value:

  • design-time substitution: The variable is used in a block that is added to a library. When the block is used, that is, it is dragged from the library listing onto the visualization page, then the user is prompted to provide specific values for the used block variables. This is useful e.g. to prepare a lighting control block in the library. When the block is instantiated on a page then specific parts of ItemIDs are replaced while other properties remain constant.

  • run-time substitution: The variable is used in a visualization element. When the element is displayed the variable is substituted by its specific value. Variables of this kind can be defined for layers, pages, groups and other visual elements.

Variables for design-time substitution

Code

Syntax

Description

Code

Syntax

Description

BK

{BK:<var name>}

Definies a block variable.

Block variables are replaced during design-time when a library element is instantiated on a visualization page.

  • Set up the library-element-to-be and insert the variable syntax when needed, e.g. as part of an item ID.

  • Add the element to the library

  • Use the library element by dragging it onto the page. You will be prompted to enter specific values for the used block variables:

  • All occurrences of variables in the inserted block are replaced by the provided values.

Variables for run-time substitution

Click menu Views / Variables to trigger visibility of the Variables pane. It contains a list of variables available to the current selection. Following variable types are available:

Code

Syntax

Description

Notes

Code

Syntax

Description

Notes

MA

{MA:<var name>}

Variable of parent object (sequence: GR/LA/PG/WS)



GR

{GR:<var name>}

Variable of a group object



LA

{LA:<var name>}

Variable of a layer object



PG

{PG:<var name>}

Variable of a page object



WS

{WS:<var name>}

Variable of a workspace object



OB

{OB:<var name>}

Variable of the current graphic object



OV

{OV:<graphic object id>.<var name>}

{OV:this.<var name>}

Object variable of the graphic object with the given ID.

The referenced object has to be on the same visualization page as the referencing object.

Use "this" for the <graphic object id> to get properties of the current object.



IV

{IV:<Item ID>}

{IV:this}

Item value

"this" uses the value of the last item ID written to the control



IP

{IP:<Item ID>.<Property ID>}

{IP:this.<Property ID>}

Value of an item’s property (e.g. {IP:"NETx\VIRTUAL\Simulation\Device\Fassade".3 } yields the value of property ID 3 (i.e. Quality) of the item).

"this" uses the last item written to the control



CH

{CH:<character code>}

Special character. Possible character codes are

  • NL: newline



SV

{SV:<var name>}

System variable. Possible variable names are

  • USERNAME: name of the current user

  • PAGENAME: name of the current page

  • PROJECTNAME: name of the running visualization project

  • DEVICENAME: name of the current device







available since 4.2.2061

VT

{VT:<key>.<index value>}

Variable of Excel file nxaVarTable.xslx (in Visualization project's DataFiles folder) 

available since 4.1.2000

OT

{OT:<index value>}

The control name must be identically with the variable name within the first column of the Excel file.

available since 4.1.2000

EV

{EV:<mathematical expression>}

Evaluates a mathematical expression, e.g. 

{EV:"(500+200)/{PG:Eval}"}

adds the constants 500 and 200 and divides the result by the value of the page variable (PG) "Eval". The original expression is replaced by the arithmetic result before further processing.

available in web from 4.1.2010

internally, a .NET DataColumn.Expression is used

TT

{TT:<translation key>}

Yields the translation of the provided translation key depending on the value of the NXA_LANGUAGE workspace variable.

available since 4.2.1010

PR

{PR:<prop name>}

Property value of the current graphic object (e.g. {PR:WIDTH} – yields the value of the WIDTH property of the graphic object).

available since 4.2.1000

OP

{OP:<graphic object id>.<prop name>}

{OP:this.<prop name>}

Property value of the graphic object (e.g. {OP:Image1.WIDTH} – yields the value of the WIDTH property of the graphic object “Image1”)

The referenced object has to be on the same visualization page as the referencing object.

Use this for the graphic object id to get properties of the current object.

available since 4.2.1000

IE

{IE:<Item ID>}

Item Exists  - Variable provides existence of Item ID or Item Branch. (e.g. {IE:"NETx\VAR\Boolean"}). True if Item ID or branch exists – false otherwise.

available since 4.2.2065