internal static ICollection <FilteredIncludeExpression> MapFilteredIncludes <TModel, TData>(this ICollection <FilteredIncludeExpression> filteredIncludes, IMapper mapper)
{
if (filteredIncludes == null)
{
return(null);
}
LambdaExpression GetFilter(LambdaExpression nextFilter, Type sourceMemberType, Type destMemberType)
{
if (nextFilter == null)
{
return(null);
}
return((LambdaExpression)mapper.Map
(
nextFilter,
typeof(Expression <>).MakeGenericType
(
new Type[]
{
sourceMemberType.IsList()
? typeof(Func <,>).MakeGenericType(new Type[] { sourceMemberType.GetUnderlyingElementType(), typeof(bool) })
: typeof(Func <,>).MakeGenericType(new Type[] { sourceMemberType, typeof(bool) })
}
),
typeof(Expression <>).MakeGenericType
(
new Type[]
{
destMemberType.IsList()
? typeof(Func <,>).MakeGenericType(new Type[] { destMemberType.GetUnderlyingElementType(), typeof(bool) })
: typeof(Func <,>).MakeGenericType(new Type[] { destMemberType, typeof(bool) })
}
)
));
}
return(filteredIncludes.Aggregate(new List <FilteredIncludeExpression>(), (list, next) =>
{
if (next.Include == null)
{
throw new ArgumentNullException("FilteredIncludeExpression.Include is required.");
}
//Map with member converted to object
LambdaExpression mappedInclude = mapper.MapExpressionAsInclude <Expression <Func <TData, object> > >(next.Include);
//Get the member expression as an "uncast" member expression
MemberExpression mappedIncludeMemberExpression = mappedInclude.Body.GetMemberExpression();
//Uncast expression's member type for the selected member
Type destMemberType = mappedIncludeMemberExpression.GetMemberType();
//Uncast expression's member type for the source's selected member
Type sourceMemberType = next.Include.Body.GetMemberExpression().GetMemberType();
//Recreate the lanbda expression so it is strongly typed. For collections the type must be IEnumerable<TProperty>.
//EntityEntry<T>.Collection expects an expression selector of type Expression<Func<T, IEnumerable<TProperty>>>
mappedInclude = Expression.Lambda
(
typeof(Func <,>).MakeGenericType
(
new Type[]
{
typeof(TData),
destMemberType.IsList()
? typeof(IEnumerable <>).MakeGenericType(new Type[] { destMemberType.GetUnderlyingElementType() })
: destMemberType
}
),
mappedIncludeMemberExpression,
mappedInclude.Parameters[0]
);
list.Add
(
new FilteredIncludeExpression
{
Include = mappedInclude,
Filter = GetFilter(next.Filter, sourceMemberType, destMemberType),
FilteredIncludes = next.FilteredIncludes == null ? null : (ICollection <FilteredIncludeExpression>)MAP_FILTERED_INCLUDES_METHOD.GetMethod().MakeGenericMethod
(
/*TModel*/ sourceMemberType.IsList() ? sourceMemberType.GetUnderlyingElementType() : sourceMemberType, //should not be a literal type. A flattened include should not have child includes
/*TData*/ destMemberType.IsList() ? destMemberType.GetUnderlyingElementType() : destMemberType
).Invoke(null, new object[] { next.FilteredIncludes, mapper })
}
);
return list;
}));
}