Add/Modify/Remove custom attribute using COM API

By Adam Nagy

If you'd like to add user data to the selected item or change its existing data, then you need to populate a property vector with all the properties the user data will contain and then add it to the selected item's GUI property node.

In case of modifying user data you need to recreate the use data with the required modifications and then overwrite the existing one. If first parameter of SetUserDefined() is 0, then a new User Data will be created, otherwise an exisiting one will be overwritten.

If you want to remove a single item in a user data, then you just have to omit it when you recreate the property vector, but if you want to remove the whole user data property collection then you need to call RemoveUserDefined() with the index of the user data you are trying to remove.

Here is a sample code written in .NET using the COM API of Navisworks:

Imports NavisWorks8
Imports NavisworksAPI8
Imports NavisworksAPI8.nwEObjectType
 
Public Class Form1
 
  Dim nwDoc As New Document
  Dim nwState As InwOpState10
 
  ' Open a Navisworks document
  Private Sub btnOpen_Click( _
    ByVal sender As System.Object, _
    ByVal e As System.EventArgs _
  ) Handles btnOpen.Click
    nwDoc.OpenFile( _
      "C:Program FilesAutodeskNavisworks Manage 2011apiCOM" + _
      "examplesgatehouse.nwd")
    nwState = nwDoc.State
    nwDoc.Visible = True
  End Sub
 
  ' Add User Data MyAttributeUserName with two items in it
  Private Sub btnAddUserData_Click( _
    ByVal sender As System.Object, _
    ByVal e As System.EventArgs _
  ) Handles btnAddUserData.Click
    If nwState.CurrentSelection.Paths.Count  1 Then
      MsgBox("Select an item first")
    End If
 
    Dim nwPath As InwOaPath = _
      nwState.CurrentSelection.Paths(1)
 
    Dim nwProps As InwOaPropertyVec = _
      nwState.ObjectFactory(eObjectType_nwOaPropertyVec)
 
    Dim nwProp1 As InwOaProperty = _
      nwState.ObjectFactory(eObjectType_nwOaProperty)
    nwProp1.name = "MyPropertyName1"
    nwProp1.value = "MyPropertyValue1"
    nwProps.Properties.Add(nwProp1)
 
    Dim nwProp2 As InwOaProperty = _
      nwState.ObjectFactory(eObjectType_nwOaProperty)
    nwProp2.name = "MyPropertyName2"
    nwProp2.value = "MyPropertyValue2"
    nwProps.Properties.Add(nwProp2)
 
    Dim nwNode As InwGUIPropertyNode2 = _
      nwState.GetGUIPropertyNode(nwPath, True)
    nwNode.SetUserDefined(0, "MyAttributeUserName", _
      "MyAttributeInternalName", nwProps)
  End Sub
 
  ' Modify the value of MyPropertyName1 in MyAttributeUserName
  Private Sub btnModifyUserDataItem_Click( _
    ByVal sender As System.Object, _
    ByVal e As System.EventArgs _
  ) Handles btnModifyUserDataItem.Click
    If nwState.CurrentSelection.Paths.Count  1 Then
      MsgBox("Select an item first")
    End If
 
    Dim nwPath As InwOaPath = _
      nwState.CurrentSelection.Paths(1)
 
    Dim nwProps As InwOaPropertyVec = _
      nwState.ObjectFactory(eObjectType_nwOaPropertyVec)
 
    Dim nwNode As InwGUIPropertyNode2 = _
      nwState.GetGUIPropertyNode(nwPath, True)
 
    Dim index As Integer = 1
 
    For Each nwAtt As InwGUIAttribute2 In nwNode.GUIAttributes()
      If Not nwAtt.UserDefined Then Continue For
 
      If Not nwAtt.ClassUserName = "MyAttributeUserName" Then
        index += 1
        Continue For
      End If
 
      For Each nwProp As InwOaProperty In nwAtt.Properties()
        Dim nwNewProp As InwOaProperty = _
          nwState.ObjectFactory(eObjectType_nwOaProperty)
 
        nwNewProp.name = nwProp.name
        nwNewProp.value = nwProp.value
 
        If nwNewProp.name = "MyPropertyName1" Then
          nwNewProp.value += "-modified"
        End If
 
        nwProps.Properties.Add(nwNewProp)
      Next
 
      nwNode.SetUserDefined(index, nwAtt.ClassUserName, _
        nwAtt.ClassName, nwProps)
 
      Exit For
    Next
  End Sub
 
  ' Remove one of the items in the user data we previously added
  Private Sub btnRemoveUserDataItem_Click( _
    ByVal sender As System.Object, _
    ByVal e As System.EventArgs _
  ) Handles btnRemoveUserDataItem.Click
    If nwState.CurrentSelection.Paths.Count  1 Then
      MsgBox("Select an item first")
    End If
 
    Dim nwPath As InwOaPath = _
      nwState.CurrentSelection.Paths(1)
 
    Dim nwProps As InwOaPropertyVec = _
      nwState.ObjectFactory(eObjectType_nwOaPropertyVec)
 
    Dim nwNode As InwGUIPropertyNode2 = _
      nwState.GetGUIPropertyNode(nwPath, True)
 
    Dim index As Integer = 1
 
    For Each nwAtt As InwGUIAttribute2 In nwNode.GUIAttributes()
      If Not nwAtt.UserDefined Then Continue For
 
      If Not nwAtt.ClassUserName = "MyAttributeUserName" Then
        index += 1
        Continue For
      End If
 
      For Each nwProp As InwOaProperty In nwAtt.Properties()
        If nwProp.name = "MyPropertyName1" Then Continue For
 
        Dim nwNewProp As InwOaProperty = _
          nwState.ObjectFactory(eObjectType_nwOaProperty)
 
        nwNewProp.name = nwProp.name
        nwNewProp.value = nwProp.value
 
        nwProps.Properties.Add(nwNewProp)
      Next
 
      nwNode.SetUserDefined(index, nwAtt.ClassUserName, _
        nwAtt.ClassName, nwProps)
 
      Exit For
    Next
  End Sub
 
  ' Remove MyAttributeUserName completely
  Private Sub btnRemoveUserData_Click( _
    ByVal sender As System.Object, _
    ByVal e As System.EventArgs _
  ) Handles btnRemoveUserData.Click
    If nwState.CurrentSelection.Paths.Count  1 Then
      MsgBox("Select an item first")
    End If
 
    Dim nwPath As InwOaPath = _
      nwState.CurrentSelection.Paths(1)
 
    Dim nwProps As InwOaPropertyVec = _
      nwState.ObjectFactory(eObjectType_nwOaPropertyVec)
 
    Dim nwNode As InwGUIPropertyNode2 = _
      nwState.GetGUIPropertyNode(nwPath, True)
 
    Dim index As Integer = 1
 
    For Each nwAtt As InwGUIAttribute2 In nwNode.GUIAttributes()
      If Not nwAtt.UserDefined Then Continue For
 
      If Not nwAtt.ClassUserName = "MyAttributeUserName" Then
        index += 1
        Continue For
      End If
 
      nwNode.RemoveUserDefined(index)
 
      Exit For
    Next
  End Sub
End Class