In this section, we explore how to modify an existing family instance. We select all doors in current document, move them up by 0.2 feet and widen them.

To begin with, we add a new command to the Labs2 module. Retrieve all doors in the current document using filters. Go through the returned ElementSet and move doors up using the Document.Move() method. Increasing the door width can be achieved by changing the corresponding parameter value. Before running the command, please ensure that there is at least one door in the model. The model created in Lab2-0 is an optional document to work on.

  /// <summary>
  /// Edit all doors in the current project.
  /// Move the doors up 0.2 feet via Document.Move() method.
  /// and widen the door 1 foot by changing the Parameter value.
  /// </summary>
  public class Lab2_4_EditFamilyInstance : IExternalCommand
  {
    public CmdResult Execute(
      ExternalCommandData commandData,
      ref string msg, ElementSet els )
    {
      Application app = commandData.Application;
      Document doc = app.ActiveDocument;
      try
      {
        // find doors in the model by filter:
        Filter filterDoor = app.Create.Filter.NewCategoryFilter( BuiltInCategory.OST_Doors );
        Filter filterFamilyInstance = app.Create.Filter.NewTypeFilter(typeof(FamilyInstance));
        Filter filterAnd = app.Create.Filter.NewLogicAndFilter(filterDoor, filterFamilyInstance);
        List<Element> doors = new List<Element>();
        doc.get_Elements( filterAnd, doors );
        foreach( FamilyInstance door in doors )
        {
          // move door up 0.2 feet:
          XYZ xyzVector = new XYZ( 0, 0, 0.2 );
          doc.Move( door, xyzVector );
          // widen the door by changing parameter value:
          Parameter par = door.Symbol.get_Parameter( BuiltInParameter.WINDOW_WIDTH );
          if( null != par )
          {
            double width = par.AsDouble();
            width += 1.0;
            par.Set(width);
          }
        }
      }
      catch( Exception ex )
      {
        LabUtils.InfoMsg( ex.Message );
      }
      return CmdResult.Succeeded;
    }
  }
  #endregion // Lab2_4_EditFamilyInstance

#Region "Lab2_4_EditFamilyInstance"
    ''' <summary>
    ''' Edit all doors in the current project.
    ''' Move the doors up 0.2 feet via Document.Move() method.
    ''' Widen the door 1 foot by changing the Parameter value.
    ''' </summary>
    Public Class Lab2_4_EditFamilyInstance
        Implements IExternalCommand

        Public Function Execute( _
                ByVal commandData As ExternalCommandData, _
                ByRef msg As String, _
                ByVal els As ElementSet) _
                As IExternalCommand.Result _
                Implements IExternalCommand.Execute

            Dim app As Application = commandData.Application
            Dim doc As Document = app.ActiveDocument
            Dim ss As ElementSet = doc.Selection.Elements

            'Find the destination door in the model by Filter
            Try
                Dim filterDoor As Filter = app.Create.Filter.NewCategoryFilter(BuiltInCategory.OST_Doors)
                Dim filterFamilyInstance As Filter = app.Create.Filter.NewTypeFilter(GetType(FamilyInstance))
                Dim filterAnd As Filter = app.Create.Filter.NewLogicAndFilter(filterDoor, filterFamilyInstance)
                Dim listDoors As List(Of Element) = New List(Of Element)()
                Dim bRet As Boolean = doc.Elements(filterAnd, listDoors)
                'Edit all doors in current document.
                Dim door As FamilyInstance = Nothing
                For Each elem As Element In listDoors
                    door = TryCast(elem, FamilyInstance)
                    If door IsNot Nothing Then
                        'Move up the door 0.2 feet.
                        Dim xyzVector As Autodesk.Revit.Geometry.XYZ
                        xyzVector = New Autodesk.Revit.Geometry.XYZ(0, 0, 0.2)
                        doc.Move(door, xyzVector)
                        'Widen the door by changing Parameter value.
                        Dim par As Parameter = door.Symbol.Parameter(BuiltInParameter.WINDOW_WIDTH)
                        If par IsNot Nothing Then
                            Dim width As Double = par.AsDouble()
                            width += 1.0
                            par.Set(width)
                        End If
                    End If
                Next elem
            Catch ex As Exception
                MsgBox(ex.Message)
            End Try

            Return IExternalCommand.Result.Succeeded

        End Function
    End Class

#End Region

Compile and link the project and update the Revit.ini file accordingly.

Run and debug the command and discuss the code with the course instructor and your peers.