This example demonstrates how you can provide custom editors for report parameters of arbitrary types. In particular, it shows how to utilize a ComboBoxEdit as an editor for a custom report parameter specifying a collection of elements.
To provide the described functionality, implement a custom parameter template selector and assign it to the PatameterTemplateSelector property of the DocumentViewer's ParametersPanel. In this example the custom parameters template selector extends the base ParameterTemplateSelector class with the capability to provide a custom editor template for a parameter with a specific name. The custom editor template is declared in XAML.
To validate a parameter value specified by a user, handle the ParametersModel.Validate event. In this example the parameters validation is used to reject the value of the catNames parameter, specified by a user, provided that it contains an empty list.