public static IEnumerable <TType> Create <TType>(
IEnumerable <TType> collection,
IList <SortingObject> ascendingSortings,
IList <SortingObject> descendingSortings)
where TType : class
{
Guard.Requires(ascendingSortings, "sortingSettings").IsNotNull();
Guard.Requires(ascendingSortings, "sortingSettings").IsNotNull();
itemParameter = Expression.Parameter(typeof(TType), "item");
IOrderedEnumerable <TType> result = null;
Expression propertyAccessor;
if (ascendingSortings.Count > 0)
{
propertyAccessor = RecursivelyPropertyInfoGetter.CreatePropertyExpression(itemParameter, ascendingSortings[0].Prop);
propertyAccessor = Expression.Convert(propertyAccessor, typeof(object));
result = collection.OrderBy(Expression.Lambda <Func <TType, object> >(propertyAccessor, itemParameter).Compile());
for (int i = 1; i < ascendingSortings.Count; i++)
{
propertyAccessor = RecursivelyPropertyInfoGetter.CreatePropertyExpression(itemParameter, ascendingSortings[i].Prop);
result = ApplySortExpressionAscending(result, propertyAccessor);
}
}
if (descendingSortings.Count > 0)
{
propertyAccessor = RecursivelyPropertyInfoGetter.CreatePropertyExpression(itemParameter, descendingSortings[0].Prop);
propertyAccessor = Expression.Convert(propertyAccessor, typeof(object));
if (result == null)
{
result = collection.OrderByDescending(Expression.Lambda <Func <TType, object> >(propertyAccessor, itemParameter).Compile());
}
else
{
result = result.ThenByDescending(Expression.Lambda <Func <TType, object> >(propertyAccessor, itemParameter).Compile());
}
for (int i = 1; i < descendingSortings.Count; i++)
{
propertyAccessor = RecursivelyPropertyInfoGetter.CreatePropertyExpression(itemParameter, descendingSortings[i].Prop);
result = ApplySortExpressionDescending(result, propertyAccessor);
}
}
return(result);
}
private static Expression ConcatenateAndOrExpressions(
IEnumerable <Filter> filters,
ParameterExpression itemParameter,
Type filterableClassType)
{
Expression where = null;
MemberExpression property;
Expression filterExpression;
if (filters != null)
{
foreach (var filter in filters)
{
property = RecursivelyPropertyInfoGetter.CreatePropertyExpression(itemParameter, filter.PropertyName);
filter.Value = ValueParser.ParseValueToPropertyType(property, filter.Value);
filterExpression = CompareExpressionByOperator(
filter.Operator,
property,
Expression.Constant(filter.Value));
if (filter.OrFilters != null && filter.OrFilters.Count > 0)
{
Expression filtersExpressions = ConcatenateAndOrExpressions(filter.OrFilters, itemParameter, filterableClassType);
if (filtersExpressions != null)
{
filterExpression = Expression.OrElse(filterExpression, filtersExpressions);
}
}
if (where != null)
{
where = Expression.AndAlso(where, filterExpression);
}
else
{
where = filterExpression;
}
}
}
return(where);
}
