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FilteredElementCollector Class

Filtered Element Collector Class

This class is used to search, filter and iterate through a set of elements.
Inheritance Hierarchy
System Object
Autodesk.Revit.DB FilteredElementCollector

Namespace: Autodesk.Revit.DB
Assembly: RevitAPI (in RevitAPI.dll) Version: 25.0.0.0 (25.0.0.0)
Syntax 
public class FilteredElementCollector : IEnumerable<Element>, 
	IDisposable

The FilteredElementCollector type exposes the following members.

Constructors
Name Description
Public method FilteredElementCollector(Document) Constructs a new FilteredElementCollector that will search and filter the set of elements in a document.
Public method Code example FilteredElementCollector(Document, ElementId) Constructs a new FilteredElementCollector that will search and filter the visible elements in a view.
Public method FilteredElementCollector(Document, ICollection ElementId ) Constructs a new FilteredElementCollector that will search and filter a specified set of elements.
Public method FilteredElementCollector(Document, ElementId, ElementId) Constructs a new FilteredElementCollector that will search and filter the visible elements from a Revit link in a host document view.
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Properties
Name Description
Public property IsValidObject Specifies whether the .NET object represents a valid Revit entity.
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Methods
Name Description
Public method ContainedInDesignOption Applies an ElementDesignOptionFilter to the collector.
Public method Dispose Releases all resources used by the FilteredElementCollector
Public method Equals Determines whether the specified object is equal to the current object.
(Inherited from Object )
Public method Excluding Applies an ExclusionFilter to the collector.
Public method Code example FirstElement Returns the first element to pass the filter(s).
Public method Code example FirstElementId Returns the id of the first element to pass the filter(s).
Protected method GetBasicIEnumerator Returns an enumerator that iterates through a collection.
Public method GetElementCount Gets the number of elements in your current filter.
Public method Code example GetElementIdIterator Returns an element id iterator to the elements passing the filters.
Public method Code example GetElementIterator Returns an element iterator to the elements passing the filters.
Public method GetEnumerator Returns an enumerator that iterates through a collection.
Public method GetHashCode Serves as the default hash function.
(Inherited from Object )
Public method GetType Gets the Type of the current instance.
(Inherited from Object )
Public method IntersectWith Intersects the set of elements passing the filter in this collector with the set of elements passing the filter in another collector.
Public method Static member IsViewValidForElementIteration Identifies if the particular element is valid for iteration of drawn elements.
Public method Code example OfCategory Applies an ElementCategoryFilter to the collector.
Public method OfCategoryId Applies an ElementCategoryFilter to the collector.
Public method Code example OfClass Applies an ElementClassFilter to the collector.
Public method OwnedByView Applies an ElementOwnerViewFilter to the collector.
Public method ToElementIds Returns the complete set of element ids that pass the filter(s).
Public method ToElements Returns the complete set of elements that pass the filter(s).
Public method ToString Returns a string that represents the current object.
(Inherited from Object )
Public method UnionWith Unites the set of elements passing the filter in this collector with the set of elements passing the filter in another collector.
Public method WhereElementIsCurveDriven Applies an ElementIsCurveDrivenFilter to the collector.
Public method WhereElementIsElementType Applies an ElementIsElementTypeFilter to the collector.
Public method WhereElementIsNotElementType Applies an inverted ElementIsElementTypeFilter to the collector.
Public method WhereElementIsViewIndependent Applies an ElementOwnerViewFilter to the collector.
Public method WherePasses Applies an element filter to the collector.
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Remarks

Developers can assign a variety of conditions to filter the elements that are returned. This class requires that at least one condition be set before making the attempt to access the elements.

Revit will attempt to organize the filters in order to minimize expansion of elements regardless of the order in which conditions and filters are applied.

There are three groups of methods that you can use on a given collector once you have applied filter(s) to it. One group provides collections of all passing elements, a second finds the first match of the given filter(s), and a third provides an iterator that is evaluated lazily (each element is tested by the filter only when the iterator reaches it). You should only use one of the methods from these group at a time; the collector will reset if you call another method to extract elements. Thus, if you have previously obtained an iterator, it will be stopped and traverse no more elements if you call another method to extract elements.

In .NET, this class supports the IEnumerable interface for Elements. You can use this class with LINQ queries and operations to process lists of elements. Note that because the ElementFilters and the shortcut methods offered by this class process elements in native code before their managed wrappers are generated, better performance will be obtained by using as many native filters as possible on the collector before attempting to process the results using LINQ queries.

One special consideration when using this class in .NET: the debugger will attempt to traverse the members of the collector because of its implementation of IEnumerable. You may see strange results if you also attempt to extract the first element or all elements from the collector while the debugger is also looking at the contents of the collector.

See Also