Calculated Field

The Calculated Field Transformation enables a user to create new column values by applying expressions, the result of which can be a newly defined column or it can replace the value in an existing one.

For example, the Agent could convert a temperature attribute on the incoming payload from Celsius to Fahrenheit - and either replace the temperature value or add a new attribute to the outgoing payload.

Statements can be written using a subset of the C# syntax. Refer to the example section for sample expressions and supported operations.

Details for an example and its configuration can be found in the How to Use section.

Pre-requisites

None at this time

Limitations

Not every C# syntax is supported. Here are some examples of NOT supported features:

• Multiline expressions

• for/foreach/while/do operators

• Array/list/dictionary initialization

• Explicit generic invocation (like method<type>(arg))

• Lambda/delegate declaration (delegate and lamda are only supported as variables or parameters or as a return type of the expression)

• Array/list/dictionary element assignment (set indexer operator)

• Other operations on dynamic objects (only property, method invocation, and index now are supported)

Current Version

• Download the Calculated Field Transformation v3.46

Please contact XMPro if you're looking for an older version of this Agent.

Release Notes

Version	Date	Description
v3.46	27 Aug 2024	Support an option to process records separately so that an error doesn't stop the execution of a batch.
v3.45	10 Apr 2024	Downgraded Newtonsoft.Json to v11.0.1. Backward compatible with older Stream Host versions.
v3.44	29 Feb 2024	Added circular dependency check in the ParseExpression function. Note: this version is only supported on Stream Host v4.4.0 and v4.4.1.
v3.43	26 Jun 2023	Fixed parsing error when braces are inside quotations. Fixed parsing of column names used in an expression.
v3.42	07 Sep 2022	Repackaged to include the Agent's Category.
v3.41	28 Apr 2021	Fixed repetitive NEW_ prefixes added to an new column internally.
v3.40	13 Nov 2020	Added better error messages.
v3.39	26 Oct 2020	Grid converted to edit list and added multiline expression support.
v3.381	30 Jul 2021	Fixed repetitive NEW_ prefixes added to an new column internally using base code of v3.38. This is an interim version which doesn't support 'EditList' control available in latest XMIoT Framework.
v3.38	26 Oct 2020	Fix existing columns being deleted.
v3.37	06 Aug 2020	Fix to nested variable expressions when also using { }.
v3.35	15 Jul 2020	Added support for variable expressions using [ ].
v3.34	26 May 2020	Upgraded validation to check if each expression is valid.
v3.33	21 May 2020	Added proper hyphen support.
v3.31	13 May 2020	Added column name support for ' ', '_', and numbers at the start of the column.
v3.30	27 Feb 2020	Fixed issue with expression not parsing on start
v3.29	24 Feb 2020	Fixed expression parsing so users can use True/False properly for Boolean values.
v3.27	03 Feb 2020	Fixed issue where expressions replace a column's value.
v3.26	03 Feb 2020	Improved exception messages and fixed errors with Boolean expressions to support XMIoT Boolean Casing.
v3.25	27 Jan 2020	Reworked expression parsing to no longer be reliant on System.Dynamic.Linq.Core reflections.
v3.14	09 Sep 2019	Support using one calculated field in another calculated field's expression.
v3.13	09 Sep 2019	Fixed issues with Payload selection.
v3.12	04 Sep 2019	Upgraded System.Linq.Dynamic.Core.
v3.11	27 Aug 2019	Support specifying Existing With New or only New columns as output.
v3.10	04 Mar 2019	Added validation for field identifiers. Added Error output when calculation fails.
v3.09	21 Jun 2019	Changed name to Calculated Field and updated icon.
v3.08	04 Mar 2019	Updated help URL
v3.07	22 May 2018	Fixed outputs that overwrite input fields not having the specified output type.
v3.06	11 May 2018	Added DateTime type to list of derived output types.
v3.05	10 May 2018	Fixed null-reference exceptions in GetOutputAttributes.
v3.04	10 May 2018	Fixed "ToInt is not a valid method" exception.
v3.03	10 May 2018	Fixed "Operator cannot be applied to operands of type Object and ..." exceptions.
v3.02	26 Apr 2018	Updated DLL.
v3.01	19 Apr 2018	Changed Agent state to Virtual.
v3.00	19 Apr 2018	Initial Release.