private static T GetPropertyValue <T>(this IEdmModel model, IEdmStructuredValue context, IEdmEntityType contextType, IEdmValueTerm term, IEdmProperty property, string qualifier, Func <IEdmExpression, IEdmStructuredValue, T> evaluator)
{
IEnumerable <IEdmValueAnnotation> annotations = model.FindVocabularyAnnotations <IEdmValueAnnotation>(contextType, term, qualifier);
if (annotations.Count() != 1)
{
throw new InvalidOperationException("Type " + contextType.ToTraceString() + " must have a single annotation with term " + term.ToTraceString());
}
var annotationValue = annotations.Single().Value as IEdmRecordExpression;
if (annotationValue == null)
{
throw new InvalidOperationException("Type " + contextType.ToTraceString() + " must have a single annotation containing a record expression with term " + term.ToTraceString());
}
var propertyConstructor = annotationValue.FindProperty(property.Name);
return(propertyConstructor != null?evaluator(propertyConstructor.Value, context) : default(T));
}