Namespace: Autodesk.Revit.DB Class: Document

Document.GetUnusedElements

Method

Description:
Returns the list of element ids that are not used and can be deleted from the document.

Remarks:
This method returns unused element ids that are available in the Purge Unused window in the Revit. To get unused elements that do not have a category assigned add INVALID to the collection of categories. If the input categories collection is empty, the method returns all unused elements in the document.

Syntax

public ISet<ElementId> GetUnusedElements(
	ISet<ElementId> categories
)

Public Function GetUnusedElements ( 
	categories As ISet(Of ElementId)
) As ISet(Of ElementId)

public:
ISet<ElementId^>^ GetUnusedElements(
	ISet<ElementId^>^ categories
)

member GetUnusedElements : 
        categories : ISet<ElementId> -> ISet<ElementId>

Examples

public void DeleteAllUnused(Autodesk.Revit.DB.Document document)
{
   using (Transaction transaction = new Transaction(document, "Delete unused elements"))
   {
      transaction.Start();

      ISet<ElementId> unusedElementIds = document.GetUnusedElements(new HashSet<ElementId>());
      while (unusedElementIds.Any())
      {
         document.Delete(unusedElementIds);
         unusedElementIds = document.GetUnusedElements(new HashSet<ElementId>());
      }

      transaction.Commit();
   }
}

public void GetUnusedElements(Autodesk.Revit.DB.Document document)
{
   // Get all unused elements in the document
   var allUnusedElementIds = document.GetUnusedElements(new HashSet<ElementId>());

   // Get unused elements without a category
   var unusedElementIdsWithNoCategory = document.GetUnusedElements(new HashSet<ElementId>() { new ElementId(BuiltInCategory.INVALID) });

   // Get unused wall and floors types
   HashSet<ElementId> categoriesToPurge = new HashSet<ElementId>
   {
      new ElementId(BuiltInCategory.OST_Walls),
      new ElementId(BuiltInCategory.OST_Floors)
   };

   var unusedElementIds = document.GetUnusedElements(categoriesToPurge);
}

     Public Sub DeleteAllUnused(ByVal document As Document)
         Using transaction As Transaction = New Transaction(document, "Delete unused elements")
             transaction.Start()

             Dim unusedElementIds As ISet(Of ElementId) = document.GetUnusedElements(New HashSet(Of ElementId)())
             While unusedElementIds.Any()
                 document.Delete(unusedElementIds)
                 unusedElementIds = document.GetUnusedElements(New HashSet(Of ElementId)())
             End While

             transaction.Commit()
         End Using
     End Sub

     Public Sub GetUnusedElements(ByVal document As Document)
         ' Get all unused elements in the document
         Dim allUnusedElementIds = document.GetUnusedElements(New HashSet(Of ElementId)())

         ' Get unused elements without a category
         Dim unusedElementIdsWithNoCategory = document.GetUnusedElements(New HashSet(Of ElementId)() From {
                New ElementId(BuiltInCategory.INVALID)
            })

         ' Get unused wall and floors types
         Dim categoriesToPurge As HashSet(Of ElementId) = New HashSet(Of ElementId) From {
   New ElementId(BuiltInCategory.OST_Walls),
   New ElementId(BuiltInCategory.OST_Floors)
}

         Dim unusedElementIds = document.GetUnusedElements(categoriesToPurge)
     End Sub

Parameters

Parameter	Type	Description
categories	ISet	Collection of categories to check for unused elements.

Return Value

Type	Description
ISet	Unused elements that can be deleted from the document.

Exceptions

Exception	Condition
ArgumentNullException	A non-optional argument was null