Post and Element Type Parameters

This is the 1024th post on The Building Coder, just to top off our recent 5-year and 1000th post celebration.

The decimal number 1024 equals 2^10, i.e. in binary format, hence the large number of zeroes in the title :-)

I am also still away on vacation and this is the second post in my absence – or 10th, in binary format :-) – dealing with retrieving ElementType parameters, the ADN Xtra labs built-in parameter checker and a BipChecker update for Revit 2014.

Meanwhile, I hope you are enjoying the break as much as I am :-)

Retrieving ElementType Parameters

I want to present a small enhancement to the built-in parameter checker included in the ADN Xtra labs.

The reason for looking at it again is to answer the following frequently recurring question:

Question: I know how to retrieve the element properties form an object, e.g. a column instance, using the Element.Parameters collection.

However, how can I access the column type properties, please?

Answer: For a given element E, you can ask for the element id of its type T by calling the GetTypeId method. Pass that in to the document GetElement method, access the T object instance itself, and retrieve the Element.Parameters collection from that.

The ADN Xtra Labs Built-in Parameter Checker

The ADN Xtra labs built-in parameter checker loops over all defined BuiltInParameter enumeration entries and checks to see whether a value can be retrieved for each of the corresponding parameters on a selected element.

Please be aware that an enhanced version of this built-in parameter checker was published as a separate BipChecker add-in back in 2011. We'll take another look at that below.

The user is prompted to select an element using the GetSingleSelectedElementOrPrompt method, which supports all conceivable selection facilities, including:

It achieves this by presenting a small prompt message:

Element selection prompt

The prompt is obviously only displayed if no pre-selection was made.

The code also initialises the isSymbol flag to false:

  Element e
    = LabUtils.GetSingleSelectedElementOrPrompt(
      uidoc );
  bool isSymbol = false;

The previous code was implemented before the introduction of the Element.GetTypeId method, so it just checked for a family instance like this:

  // for a family instance, ask user whether to 
  // display instance or type parameters;
  // in a similar manner, we could add dedicated 
  // switches for Wall --> WallType,
  // Floor --> FloorType etc. ...
  if( e is FamilyInstance )
    FamilyInstance inst = e as FamilyInstance;
    if( null != inst.Symbol )
      string symbol_name
        = LabUtils.ElementDescription(
          inst.Symbol, true );
      string family_name
        = LabUtils.ElementDescription(
          inst.Symbol.Family, true );
      string msg =
      "This element is a family instance, so it "
      + "has both type and instance parameters. "
      + "By default, the instance parameters are "
      + "displayed. If you select 'No', the type "
      + "parameters will be displayed instead. "
      + "Would you like to see the instance "
      + "parameters?";
      if( !LabUtils.QuestionMsg( msg ) )
        e = inst.Symbol;
        isSymbol = true;

I updated the code to be more generic and handle all kinds of element type relationships by checking whether the GetTypeId method returns a valid element type id like this:

  ElementId idType = e.GetTypeId();
  if( ElementId.InvalidElementId != idType )
    // The selected element has a type; ask user 
    // whether to display instance or type 
    // parameters.
    ElementType typ = doc.GetElement( idType )
      as ElementType;
    Debug.Assert( null != typ,
      "expected to retrieve a valid element type" );
    string type_name = LabUtils.ElementDescription(
      typ, true );
    string msg =
      "This element has an ElementType, so it has "
      + "both type and instance parameters. By "
      + "default, the instance parameters are "
      + "displayed. If you select 'No', the type "
      + "parameters will be displayed instead. "
      + "Would you like to see the instance "
      + "parameters?";
    if( !LabUtils.QuestionMsg( msg ) )
      e = typ;
      isSymbol = true;

If an element that has a valid type assigned to it is selected, e.g. a wall, the code detects this and prompts the user to choose whether to display its instance or type properties:

Element type message

If instance properties are chosen, the following list of parameters on the wall itself is displayed:

List of instance parameters

If type properties are chosen, the parameters are retrieved from the wall type instead:

List of element type parameters

Here is version 2014.0.0.3 of the ADN Training Labs for Revit 2014 including the updated built-in parameter checker.

BipChecker Update for Revit 2014

I went on planning to implement the same enhancement in the stand-alone BipChecker add-in, only to discover two things:

  1. It has not been updated since its original publication in the year 2011, for Revit 2012.
  2. It has already implemented a more sophisticated check than the one I describe above.

To see the more sophisticated check for various kinds of element types implemented by BipChecker, please search for 'CanHaveTypeAssigned' in the initial BipChecker publication.

I updated it for Revit 2014, fixing some compilation errors and disabling the architecture mismatch warning; here is BipChecker_2014.zip containing the new version.

Back to my vacation again... Meanwhile, I wish you a wonderful time as well!