Please check this code for Getting Family Parameter GUID

[KCIM_고영빈]

using Autodesk.Revit.DB;
using Autodesk.Revit.UI;
using Autodesk.Revit.Attributes;
using Autodesk.Revit.ApplicationServices;
using System.Collections.Generic;
using System.Linq;
using System.Security.Cryptography;
using System;

namespace NewJeans
{
    [Transaction(TransactionMode.Manual)]
    public class ExtractSharedParamsGUID : IExternalCommand
    {
        public Result Execute(ExternalCommandData commandData, ref string message, ElementSet elements)
        {
            UIDocument uiDoc = commandData.Application.ActiveUIDocument;
            Document doc = uiDoc.Document;
            Application app = commandData.Application.Application;

            List<string> result = new List<string>();

            var familyInstances = new FilteredElementCollector(doc)
                               .OfClass(typeof(FamilyInstance))
                               .Cast<FamilyInstance>()
                               .ToList();

           
            List<Family> families = familyInstances
                            .Select(fi => fi.Symbol.Family)
                            .Distinct().ToList();


            foreach (Family fam in families)
            {
                Document famDoc = doc.EditFamily(fam);
                FamilyManager fm = famDoc.FamilyManager;

                using (Transaction trans = new Transaction(famDoc, "ExtractFamilyParameter"))
                {
                    trans.Start();

                    foreach (FamilyParameter p in fm.Parameters)
                    {
                        string name = p.Definition.Name;
                        string defType = p.Definition.GetType().Name;

                        if (p.IsShared)
                        {
                            if (p.Definition is ExternalDefinition extDef)
                            {
                                string guid = extDef.GUID.ToString();
                                result.Add($" {fam.Name} - {name} : Shared, GUID: {guid}");
                            }
                            else if ((p.Definition is InternalDefinition intDef))
                            {
                                string type = intDef.ToString();
                                result.Add($" {fam.Name} - {name} : Shared, but {type}");
                            }
                        }
                        else
                        {
                            result.Add($" {fam.Name} - {name} : Not Shared");
                        }
                    }

                    trans.RollBack();
                }

                famDoc.Close(false);
            }

            TaskDialog.Show("Shared Parameters", string.Join("\n", result));

            return Result.Succeeded;

        }
    }
}

this is the code and result is 

I correctly added the Shared Parameter to the family("shared2", "shared@").

When I access the parameter in the API, it shows up as InternalDefinition, even though the IsShared property returns True.

Has anyone encountered this issue before? What am I missing? How can I ensure that the Shared Parameter is recognized properly as a Shared Parameter in the API, rather than an InternalDefinition? please.... Help me

[jeremy_tammik]

Little side note: this command can probably be run in read-only mode, with no transaction. I always prefer read-only TransactionMode when it is possible. Please try it out and let us know whether that works as well.

[jeremy_tammik · Accepted solution]

It seems to me that Gemini captures, understands and explains the issue quite well. Please check this answer and let us know whether it helps resolve the issue:

• https://g.co/gemini/share/663b28169a0b

[KCIM_고영빈]

That was incredibly helpful...!! Your answer helped me so much