How to create a parameter of System.Enum type

This example demonstrates how you can define an enumeration as a report parameter of a custom type.
 
To make this parameter type (in addition to standard System.Type types) available for your end-users in the Designer, simply inherit from the ReportDesignExtension class, instantiate your custom object and override the AddParameterTypes() method. And, register the custom extension, by calling the ReportDesignExtension.RegisterExtension() method.

Then, after an end-user assigns this type for a parameter, an appropriate parameter value editor is auto-created, in accordance with the parameter type.
 
And, after specifying this parameter in the report's FilterString, this editor is shown in the report's Print Preview.
 
See also: How to serialize parameters of custom types