public static PropertiesDescriptor <T> Strings <T>(this PropertiesDescriptor <T> propertiesDescriptor, params Expression <Func <T, object> >[] excludedProperties) where T : class { // Validate parameters. if (propertiesDescriptor == null) { throw new ArgumentNullException(nameof(propertiesDescriptor)); } if (excludedProperties == null) { throw new ArgumentNullException(nameof(excludedProperties)); } // Call the implementation. return(propertiesDescriptor.StringsImplementation(null, excludedProperties)); }