Monday, November 29, 2010

By the Book Part 2 - Harvesting Families from a Project Model

This post is part 2 in response to the sample Revit API application I wrote for the book entitled "Mastering Revit Architecture 2011"...  in Chapter 24 "Under the Hood of Revit."

Well, I promised I would show you the updated family export code in my previous post "By the Book Part 1 - Harvesting Families from a Project Model."... so without further procrastination...

We'll get started off by setting the code to our export button illustrated below. All this does is hide the lower buttons to make room for the progress bar and then runs the export routine. When we're all done, we'll call the close function for the form and exit out.

''' <summary>
    ''' Export the families and then quietly close
    ''' </summary>
    ''' <param name="sender"></param>
    ''' <param name="e"></param>
    ''' <remarks></remarks>
    Private Sub ButtonExport_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ButtonExport.Click
        Me.ButtonCancel.Visible = False
        Me.ButtonExport.Visible = False
        Me.ButtonSelectAll.Visible = False
        Me.ButtonSelectNone.Visible = False
        ' We're all done
    End Sub

I guess we should get the last remaining function out of the way as well before we dive into the export function. The function below is used to verify that all characters used to create a file name are valid for the Windows OS.

''' <summary>
    ''' Make sure the path does not contain any invalid file naming characters
    ''' </summary>
    ''' <param name="fileName">The Filename to check</param>
    ''' <returns>A string</returns>
    ''' <remarks></remarks>
    Private Function CheckValidFileName(ByVal fileName As String) As String
        For Each c In Path.GetInvalidFileNameChars()
            If fileName.Contains(c) Then
                ' Invalid filename characters detected...
                ' Could either replace characters or return empty
                Return ""
            End If
        Return fileName
    End Function

The export function starts out by first verifying that at least one category has been checked for export. Then a hashtable is used as a means to reference each selection (hashtables are FAST).

''' <summary>
    ''' This routine performs the exports
    ''' </summary>
    ''' <remarks></remarks>
    Private Sub doExport()
        ' Ony export families that belong to our selected categories!
        Dim m_SelectedCategories = Me.CheckedListBoxCategories.CheckedItems
        ' Do nothing if nothing selected
        If m_SelectedCategories.Count = 0 Then
            MsgBox("You did not select any categories..." & vbCr & "Nothing to do...", _
                   MsgBoxStyle.Information, "No Categories Selected! Exiting...")
            Exit Sub
        End If
        ' A hashtable comes in handy when verifying multiple situations... or 1
        Dim m_CatHash As New Hashtable
        For Each xItemC In m_SelectedCategories
            m_CatHash.Add(xItemC.ToString, "Category")

The next thing to do is make sure the target directory exists for the export.

Try ' If the parent export directory is missing, create it
            Directory.CreateDirectory(Replace(Me.LabelExportPath.Text, "/", "\", , , CompareMethod.Text))
        Catch ex As Exception
            ' Message to show any errors
            MsgBox(Err.Description, MsgBoxStyle.Information, Err.Source)
        End Try

With the main directory created, we can continue with the element collection and progress bar setup. The filter below grabs all "Type" elements from the model and turns the result into an easy to use list of DB.Element.

' Filter to get a set of elements that are elementType 
        Dim m_SymbFilter As New DB.ElementIsElementTypeFilter
        Dim collector As New DB.FilteredElementCollector(m_Doc)
        ' Create a list from the collector
        Dim FamilySymbols As New List(Of DB.Element)
        FamilySymbols = collector.ToElements
        ' Start the progressbar
        Dim iCnt As Integer = 0
        Dim iCntFam As Integer = FamilySymbols.Count
        Me.ProgressBar1.Visible = True
        Me.ProgressBar1.Minimum = 0
        Me.ProgressBar1.Maximum = iCntFam
        Me.ProgressBar1.Value = iCnt

Now we can iterate the element list and perform the necessary exports as external RFA files.

' The export process
For Each x As DB.Element In FamilySymbols
    If (TypeOf x Is DB.FamilySymbol) Then
        Dim m_category As DB.Category = x.Category
        If Not (m_category Is Nothing) Then
            ' Is it a selected category?
            If m_CatHash.Contains(m_category.Name) Then
                Dim m_ExportPath As String = ""
                Try ' Create the subdirectory
                    m_ExportPath = Me.LabelExportPath.Text & "\" & m_category.Name & "\"
                    Directory.CreateDirectory(Replace(m_ExportPath, "/", "\", , , CompareMethod.Text))
                Catch ex As Exception
                    ' Category subdirectory exists
                End Try
                Try ' The family element
                    Dim m_FamSymb As DB.FamilySymbol = x
                    Dim m_FamInst As DB.Family = m_FamSymb.Family
                    Dim m_FamName As String = m_FamInst.Name
                    ' Verify famname is valid filename and exists
                    If Dir$(m_ExportPath + m_FamName & ".rfa") = "" And CheckValidFileName(m_FamName) <> "" Then
                        Me.LabelFileName.Text = "...\" & m_category.Name & "\" & m_FamInst.Name
                        Dim famDoc As DB.Document = m_Doc.EditFamily(m_FamInst)
                        famDoc.SaveAs(m_ExportPath + m_FamName & ".rfa")
                    End If
                Catch ex As Exception
                    ' Prevent hault on system families
                End Try
            End If
        End If
    End If
    ' Step the progress bar

That's it! Now you have the means to quickly harvest families from a Revit 2011 model.

If you have any questions or suggestions for other Revit 2011 code solutions, don't hesitate to leave a comment or ask a question.