topic Re: FilteredElementCollector -> get all instances except of category X in Revit API Forum

FilteredElementCollector -> get all instances except of category X

jnoordzij — Mon, 04 Feb 2019 13:42:07 GMT

I am filtering for FamilInstances in a doc using FilteredElementCollector.

I want to get all family instances, except the titleblocks.

public ICollection<Element> CollectFamilyInstances(Document doc)
        {
            FilteredElementCollector collector
                = new FilteredElementCollector(doc);

            ICollection<Element> collection
              = collector.OfClass(typeof(FamilyInstance))
                .ToElements();

            return collection;
        }

How can i apply a filter over this collection so that instances of category OST_TitleBlocks are omitted from this collection?

Re: FilteredElementCollector -> get all instances except of category X

jnoordzij — Mon, 04 Feb 2019 14:24:21 GMT

I do this now but there has to be a cleaner way...

public ICollection<Element> CollectFamilyInstances(Document doc)
        {
            FilteredElementCollector collector
                = new FilteredElementCollector(doc);

            ICollection<Element> collection
              = collector.OfClass(typeof(FamilyInstance))
                .ToElements();

            ICollection<Element> collection2 = new List<Element>();

            foreach (Element e in collection)
            {
                if (!e.Category.Equals(BuiltInCategory.OST_TitleBlocks))
                {
                    collection2.Add(e);
                }
            }
            
            return collection2;
        }

thanks for any extra advice on this!

Re: FilteredElementCollector -> get all instances except of category X

jnoordzij — Mon, 04 Feb 2019 14:30:41 GMT

Got it to work!

public ICollection<Element> CollectFamilyInstances(Document doc)
        {
            FilteredElementCollector collector
                = new FilteredElementCollector(doc);

            ElementCategoryFilter fi = new ElementCategoryFilter(BuiltInCategory.OST_TitleBlocks, true);

            ICollection<Element> collection
              = collector.OfClass(typeof(FamilyInstance)).WherePasses(fi)
                .ToElements();

            return collection;
        }

Re: FilteredElementCollector -> get all instances except of category X

Anonymous — Mon, 04 Feb 2019 14:36:50 GMT

Not tested, but maybe using quick filter is what you are looking for (if you want just titleblocks category):

ElementCategoryFilter titleblockfilter = new ElementCategoryFilter(BuiltInCategory.OST_TitleBlocks);
ICollection<Element> collection
              = collector.OfClass(typeof(FamilyInstance))
                .WherePasses(titleblockfilter)
                .ToElements();

Re: FilteredElementCollector -> get all instances except of category X

naveen.kumar.t — Tue, 05 Feb 2019 05:59:49 GMT

HI @jnoordzij

ExclusionFilter Class helps you to filter elements by excluding particular elements.

Exclusion Filter Class

FilteredElementCollector Collector = new FilteredElementCollector(doc).OfClass(typeof(FamilyInstance)).WhereElementIsNotElementType();
IList<ElementId> eids = Collector.ToElementIds() as IList<ElementId>;

ICollection<ElementId> exclude_elements = new FilteredElementCollector(doc).OfCategory(BuiltInCategory.OST_TitleBlocks).WhereElementIsNotElementType().ToElementIds() as ICollection<ElementId>;

ExclusionFilter EF = new ExclusionFilter(exclude_elements);
IList<ElementId> elementsAfterExclusion = Collector.WherePasses(EF).OfClass(typeof(FamilyInstance)).ToElementIds() as IList<ElementId>;

If this helped solve your problem please mark it as solution, so other users can get this solutions as well

Re: FilteredElementCollector -> get all instances except of category X

jnoordzij — Tue, 05 Feb 2019 09:53:58 GMT

In conclusion of this thread:

I haven't checked the solution provided by @naveen.kumar.t , since I found a working solution beforehand, but that solution might also work.

My own solution was that the ElementCategoryFilter has an additional boolean option that provides the option to match all elements which are NOT of the given category. So an "invert" boolean. Hence the (invert=) "true" at the end of

ElementCategoryFilter fi = new ElementCategoryFilter(BuiltInCategory.OST_TitleBlocks, true);