Let’s look at how to use the FilterInverseRule filter rule to filter element parameters in VB.NET in this article. Supposing we’d like to find all rooms with the Phase Created parameter not set as a specific value, what shall we do?
The following code does so in VB.NET:
Public Shared Function GetWallsNotInPhase(ByVal doc As RvtDocument, ByVal phase As Phase) As ICollection(Of Autodesk.Revit.DB.ElementId)
Dim provider As New Autodesk.Revit.DB.ParameterValueProvider(New Autodesk.Revit.DB.ElementId(CInt(BuiltInParameter.PHASE_CREATED)))
Dim rule1 As New Autodesk.Revit.DB.FilterElementIdRule(provider, New Autodesk.Revit.DB.FilterNumericEquals(), phase.Id)
Dim rule2 As New Autodesk.Revit.DB.FilterInverseRule(rule1)
Dim filter1 As New Autodesk.Revit.DB.ElementParameterFilter(rule2)
Return (New Autodesk.Revit.DB.FilteredElementCollector(doc)).OfClass(GetType(Wall)).WherePasses(filter1).ToElementIds()
End Function
A few highlights about the code:
• An ElementParameterFilter needs a filter rule, the FilterInverseRule in this case.
• The FilterInverseRule needs another filter rule to be inverted. We’d like to invert a FilterElementIdRule here.
• The FilterElementIdRule needs a parameter value provider (ParameterValueProvider) and a filter rule evaluator (FilterNumericRuleEvaluator), specifically the FilterNumericEquals here.
• Do not feel surprised that the FilterNumericEquals evaluator also works with the FilterElementIdRule as the ElementId is actually nothing more than an integer value.
• The ParameterValueProvider needs an argument of parameter, as the phase created parameter BuiltInParameter.PHASE_CREATED in this case.
• The parameter is represented by an ElementId, which is the numeric value of the specified BuiltInParameter.
• A fast filter, ElementClassFilter, represented by its shortcut method (OfClass), is also used to narrow down the FilteredElementCollector first. It not only speeds up the search but also makes sure only walls are returned.
Curious people may ask: how did you figure out the PHASE_CREATED of the BuiltInParameter enumerator is the right one to use?
Good question! Though we still have to make some guess and do some experiment most of times to sort things like this out, a few RevitAddinCoder coders can help make the task a lot easier:
• Parameter Infoer Coder
• Parameter Categorizer Coder
• Parameter Retriever Coder
To use the method is very straightforward. Here is some test code in VB.NET:
…
Dim phase As Autodesk.Revit.DB.Phase = CachedDoc.Phases.Item(0)
Dim ids As ICollection(Of Autodesk.Revit.DB.ElementId) = GetWallsNotInPhase(CachedDoc, phase)
TaskDialog.Show("ElementParameterFilter Test", String.Format("{0} walls are NOT in the phase created {1}.", ids.Count, phase.Name))
…
ElementParameterFilter Creator of RevitAddinCoder can create the code automatically in no time.
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