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 for 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. The reference is added under the AssemblyReferences configuration section in the application's configuration file.
<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>