Add Parameters To Element

[Anonymous]

Hello! 

I'm not a very experienced Revit developer (nor an experienced Revit user), so I'm sorry if I got something wrong.

I need to add new parameters to Revit objects via the API. I'm developing an AddIn to do so, but the parameters should be visible in this window:

(I'm sorry, I'm using the German version of Revit, but I think this is called the Properties Palette in English).

How can I add a new set of values there?

I was trying to add a new instance parameter to an existing Revit element, but I couldn't find any information on how to do so. 

It seems like I can access all parameters of an object via

element.Parameters

Which returns a ParameterSet. ParameterSet contains the method Insert, but I don't know how to use it. Moreover, in the API documentation, it says that "New parameters can be added to Elements by adding a ParameterBinding object to the Document object." What does this mean?

Or did I get this completely wrong and Instance Parameters are not what I'm looking for?

Thanks for your help!

[so-chong]

Hi,

Did you find this link?

http://www.revitapidocs.com/2018.1/7978cb57-0a48-489e-2c8f-116fa2561437.htm?section=exampleToggle

The code example also shows how to bind an instance parameter to the document.
I hope this is what you are looking for.

[JimJia · Accepted solution]

Hi, 

The Revit SDK samples have one sample named RoomSchedule which has some code snippet on shared parameter creation, you may refer to this sample for more details. 

I also copy/paste the code snippet below for your convenience:

        /// <summary>
        /// Create shared parameter for Rooms category
        /// </summary>
        /// <returns>True, shared parameter exists; false, doesn't exist</returns>
        private bool CreateMyRoomSharedParameter()
        {
            // Create Room Shared Parameter Routine: -->
            // 1: Check whether the Room shared parameter("External Room ID") has been defined.
            // 2: Share parameter file locates under sample directory of this .dll module.
            // 3: Add a group named "SDKSampleRoomScheduleGroup".
            // 4: Add a shared parameter named "External Room ID" to "Rooms" category, which is visible.
            //    The "External Room ID" parameter will be used to map to spreadsheet based room ID(which is unique)

            try
            {
                // check whether shared parameter exists
                if (ShareParameterExists(RoomsData.SharedParam))
                {
                    return true;
                }

                // create shared parameter file
                String modulePath = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);
                String paramFile = modulePath + "\\RoomScheduleSharedParameters.txt";
                if (File.Exists(paramFile))
                {
                    File.Delete(paramFile);
                }
                FileStream fs = File.Create(paramFile);
                fs.Close();

                // cache application handle
                Autodesk.Revit.ApplicationServices.Application revitApp = m_commandData.Application.Application;

                // prepare shared parameter file
                m_commandData.Application.Application.SharedParametersFilename = paramFile;

                // open shared parameter file
                DefinitionFile parafile = revitApp.OpenSharedParameterFile();

                // create a group
                DefinitionGroup apiGroup = parafile.Groups.Create("SDKSampleRoomScheduleGroup");

                // create a visible "External Room ID" of text type.
                ExternalDefinitionCreationOptions ExternalDefinitionCreationOptions = new ExternalDefinitionCreationOptions(RoomsData.SharedParam, ParameterType.Text);
                Definition roomSharedParamDef = apiGroup.Definitions.Create(ExternalDefinitionCreationOptions);

                // get Rooms category
                Category roomCat = m_commandData.Application.ActiveUIDocument.Document.Settings.Categories.get_Item(BuiltInCategory.OST_Rooms);
                CategorySet categories = revitApp.Create.NewCategorySet();
                categories.Insert(roomCat);

                // insert the new parameter
                InstanceBinding binding = revitApp.Create.NewInstanceBinding(categories);
                m_commandData.Application.ActiveUIDocument.Document.ParameterBindings.Insert(roomSharedParamDef, binding);
                return false;
            }
            catch (Exception ex)
            {
                throw new Exception("Failed to create shared parameter: " + ex.Message);
            }
        }

[Anonymous]

Thank's a lot, that helped me quite a bit!

[stever66]

I'm glad you got a solution.  You might also find this post of mine helpful:

https://forums.autodesk.com/t5/revit-api-forum/sorting-parameters-in-the-family-editor/td-p/7676931

It is basically  "A sharp macro that runs from within the family manager, and adds and sorts parameters from the shared parameters file."

Even though I made a sharp macro, the main block of code will run in Visual Studio.

[Anonymous]

Hi,

I have started to develop something similar. Is it possible to share your code here ?.

This will save me some amount of time. We can always exchange knowledge. I have started recently to do development for Revit. My target is to increas the interoperability in my workflows through managing my families using Excel sheets.

Best regards,

CadRobots

[Anonymous]

I've been struggling with a problem related to this for quite a while now. I manage to add a shared parameter to instances of elements I desire but I cannot utilise the .Set( command on it since I get an exception saying that the same parameter that I've just created is read-only. This comes down to a situation where I'm able to add a parameter and make it user modifiable but I can't modify it through the API which is absurd. Anyone's got an idea where might my mistake be?

[Anonymous]

I've just managed to avoid the read-only exception. Earlier I was trying to assign the value of the parameter to all wall objects in the project file. When I select some walls by hand and then run the command everything works. I wonder why some of the walls won't allow me to change the value from API. Does anyone know a workaround for that? There is always a risk that I might stumble upon one of those "evil walls" while selecting and then the code will fail.

[Anonymous]

Is there no other way to create an element parameter other than coding? there should be?

[stever66]

Yes, you can easily add parameters from the user interface, but please notice that this is the Revit API (i.e. coding) forum.