Extending Expressions Overview

Updated on Sep 15, 2026

Expressions can easily be extended by providing user functions written in any .NET language. This is very useful in addition to the built-in functions, providing more complex domain-specific calculations or uniform calculations because it speeds up the processing and boosts the performance. Furthermore, you can add custom aggregate functions to apply domain-specific logic while accumulating values.

In order to expose your custom functions, so they can be utilized by the Reporting engine, you have to add a reference to the assembly they are defined in. This can be done through the assemblyReferences element in the application's configuration file.

XML

<configuration>
	<configSections>
		<section name="Telerik.Reporting"
		         type="Telerik.Reporting.Configuration.ReportingConfigurationSection, Telerik.Reporting"
		         allowLocation="true"
		         allowDefinition="Everywhere"/>
	</configSections>
	<!-- … -->
	<Telerik.Reporting>
		<assemblyReferences>
			<add name="MyCustomAssembly"
			     version="1.0.0.0"/>
		</assemblyReferences>
	</Telerik.Reporting>
</configuration>

JSON

"telerikReporting": {
    "assemblyReferences": [
        {
            "name": "MyCustomAssembly",
            "version": "1.0.0.0"
        }
    ]
}

See Also

• Create User Functions
• Create User Aggregate Functions