Support for Dashboards and Chained Reports was added in v2019.1.26, v2019.2.12 and v2020.1.1.
For custom code the arguments array is structured as follows:
args[] is empty.
For .NET Assemblies the method signature is as follows:
string EventHandlerName(SessionInfo sessionInfo)
The report being saved can be accessed through the sessionInfo object by using sessionInfo.Report for Advanced Reports, CrossTabs and ExpressViews. For Dashboards and Chained Reports, use sessionInfo.ReportObject.
Expects a string return value. If null, the report will continue processing; if not null, represents the language file ID, or string text to display to the user.