public static async Task <TResult> FirstOrDefaultAsync <TResult>(this FilteredExpressionQuery <TResult> filteredExpressionQuery) where TResult : class
{
object obj = await filteredExpressionQuery.ToObjectQuery(filteredExpressionQuery.Source).FirstOrDefaultAsync();
filteredExpressionQuery.ClearInterceptors(obj);
return((TResult)obj);
}
public static async Task <List <TResult> > ToListAsync <TResult>(this FilteredExpressionQuery <TResult> filteredExpressionQuery, IQueryable <TResult> query) where TResult : class
{
IQueryable <object> runtimeTypeSelectExpressionQuery = filteredExpressionQuery.ToObjectQuery(query);
// Get result from database
List <object> listOfObjects = await runtimeTypeSelectExpressionQuery.ToListAsync();
MethodInfo castMethod = typeof(Queryable)
.GetMethod("Cast", BindingFlags.Public | BindingFlags.Static)
.MakeGenericMethod(filteredExpressionQuery.ProxyType);
// Cast list<objects> to IQueryable<runtimeType>
IQueryable castedSource = castMethod.Invoke(
null,
new Object[] { listOfObjects.AsQueryable() }
) as IQueryable;
// Create instance of runtime type parameter
ParameterExpression runtimeParameter = Expression.Parameter(filteredExpressionQuery.ProxyType, "p");
IDictionary <string, PropertyInfo> dynamicTypeFieldsDict =
filteredExpressionQuery.ProxyProperties.ToDictionary(f => f.Name.ToLowerInvariant(), f => f);
// Generate bindings from runtime type to source type
IEnumerable <MemberBinding> bindingsToTargetType = filteredExpressionQuery.SelectedProperties.Values
.Select(property => Expression.Bind(
property,
Expression.Property(
runtimeParameter,
dynamicTypeFieldsDict[property.Name.ToLowerInvariant()]
)
));
// Generate projection trom runtimeType to T and cast as IQueryable<object>
IQueryable <TResult> targetTypeSelectExpressionQuery
= ExpressionMapper.GenerateProjectedQuery <TResult>(
filteredExpressionQuery.ProxyType,
typeof(TResult),
bindingsToTargetType,
castedSource,
runtimeParameter
);
// Return list of T
return(targetTypeSelectExpressionQuery.ToList());
}