Looping through selected elements

Fred emailed and asked about how to iterate through a selection set and make a modification to each element in that set, in particular regarding adding a leader to selected text notes.

The API provides the ElementSetIterator class. I used its method MoveNext in a While loop, and this takes us through each selected element, on which you can then test for type and act accordingly.

Public Sub LoopSelectedElements()

Dim activeDoc As Document = revitApp.ActiveDocument

Dim selectionIterator As Autodesk.Revit.ElementSetIterator
selectionIterator = revitApp.ActiveDocument.Selection.Elements.ForwardIterator

'loop through iterator
While selectionIterator.MoveNext

Dim currElement As Autodesk.Revit.Element = selectionIterator.Current

'see what elements we've found
Debug.Print(currElement.Name.ToString)

'check for type and make mods
If TypeOf currElement Is Autodesk.Revit.Elements.TextNote Then
 Dim textNote As Autodesk.Revit.Elements.TextNote = currElement
 textNote.AddLeader(Enums.TextNoteLeaderTypes.TNLT_STRAIGHT_R)
End If

End While

End Sub

I didn't really test the textNote.AddLeader part. Fred reports that it works but the new leader only becomes visible when you move the textnote. Something to look into when I've got a spare five mins :)