Setting FamilyParameter via API

[mhillis]

Hello all,

I've been trying to figure out how I can set the value of a FamilyParameter with the API.  Here's the deal.

I have an add-in that's taking a family and adding some family parameters to it, like so

FamilyParameter widthParam = 
      famDoc.FamilyManager.AddParameter("Width", 
                                         BuiltInParameterGroup.PG_GENERAL, 
                                         ParameterType.HVACDuctSize, true);

Going this route, I can't figure out a way to set a value for this parameter. I've read-up this post by Jeremy - http://thebuildingcoder.typepad.com/blog/2009/11/family-parameter-value.html

However, that just covers reading the value, I was hoping I could reverse engineer it and figure out how to set the value, but no avail.

Any ideas anyone?

Thanks!

[MarryTookMyCoffe · Accepted solution]

ok, I can see why this can be confusing for you. It was for me on start to. You do all things on FamilyParameter with document.FamilyManager. I put some exemple code:

FamilyParameter familyParameter = document.FamilyManager.AddParameter("Radius", BuiltInParameterGroup.PG_GEOMETRY, ParameterType.Length, false);

document.Regenerate();
document.FamilyManager.Set( familyParameter, diameterList[i]);
document.FamilyManager.SetFormula( familyParameter, "Height * 2");

sometimes there will be problem with adding FamilyParameter to dimension try use document.Regenerate()

ps. text before 2014 are in most case not useful, they change a lot from that time.

[mhillis]

MarryTookMyCoffee,

Thank you, that was it.  I didn't realize that the FamilyManager had the Set/SetFormula methods for this purpose.

Thank you again. 

[MarryTookMyCoffe]

Glad I could help

[leandrocaplan]

Hi: I'm trying this, but it doesn't works:

using System;
using System.Collections.Generic;
using System.Linq;

using Autodesk.Revit.DB;
using Autodesk.Revit.DB.Architecture;
using Autodesk.Revit.UI;
using Autodesk.Revit.UI.Selection;
using Autodesk.Revit.ApplicationServices;
using Autodesk.Revit.Attributes;

[TransactionAttribute(TransactionMode.Manual)]
[RegenerationAttribute(RegenerationOption.Manual)]
public class EditarFamiliav2 : IExternalCommand
{
  public Result Execute(
    ExternalCommandData commandData,
    ref string message,
    ElementSet elements)
  {
	
    //Get application and document objects
    UIApplication uiApp = commandData.Application;    
    Document doc = uiApp.ActiveUIDocument.Document;


    Transaction trans = new Transaction(doc);
    trans.Start("Lab");
    
    FamilyParameter familyParameter = doc.FamilyManager.AddParameter("Radius", BuiltInParameterGroup.PG_GEOMETRY, ParameterType.Length, false);
    ElementId elemId = familyParameter.Id;
doc.Regenerate();
doc.FamilyManager.Set( familyParameter, elemId);
doc.FamilyManager.SetFormula( familyParameter, "Height * 2");
    trans.Commit();
    trans.Dispose();
    return Result.Succeeded;
  }
}

I changed the line 

document.FamilyManager.Set( familyParameter, diameterList[i]);

 for avoiding a compilation error (I don't know what "diameterList[i]" is)

Here's a screenshot of the error:

Thank you

[mhillis]

leandrocaplan,

There are two things to address.  First, you mention that you don't know what 'diameterList[i]' is. You should, it is a value that you define in your own code.

Second, the error message you're getting indicates that the Revit Add-in simply failed to execute correctly, typically because of an exception that happened somewhere in your code.  You'll need to debug your add-in using a debugger (like Visual Studio) and then see the exception happen in real time by setting your debugger to break execution when an exception happens.  From there, you should have a much better understanding of what is failing.