NuGet Package: DevExpress.Win.Reporting
public abstract class ReportDesignExtension : IRepositoryItemCreator, IDataSerializer
Public MustInherit Class ReportDesignExtension Implements IRepositoryItemCreator, IDataSerializer
To provide parameters of custom types to your report, you should create a custom report design extension, inherited from the ReportDesignExtension class.
Then, register the extension (using the ReportDesignExtension.RegisterExtension method) and associate the report with the custom extension (ReportDesignExtension.AssociateReportWithExtension).
To learn more, see Creating Custom Report Parameters.
Another scenario for using the ReportDesignExtension is the XML serialization of custom parameters and other objects.