I am trying to create a plugin inside the Revit which supposed to search on some categories(the catgories i get from an Excel sheet according to the elements) and then add new shared paramters to them , but what i found out that when i run the code it only add those new paramters to the last element was in the Excel sheet, not all the elements, and if i remove this elements, the changes will get applied only on the last element not the previou elements in the last, i dunno if its about the transaction or what exactly.
this is where is my transaction happens:

public Result Execute(ExternalCommandData commandData, ref string message, ElementSet elements)
{
    // Initialize Revit document
    UIDocument uiDoc = commandData.Application.ActiveUIDocument;
    Document doc = uiDoc.Document;

    Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);

    // Set the EPPlus license context
    ExcelPackage.LicenseContext = LicenseContext.NonCommercial;

    // Open file explorer to select the Excel file
    OpenFileDialog openFileDialog = new OpenFileDialog
    {
        Filter = "Excel Files|*.xlsx",
        Title = "Select the Excel File with Parameters"
    };

    if (openFileDialog.ShowDialog() != true)
    {
        // If no file is selected, cancel the command
        message = "No file was selected.";
        return Result.Cancelled;
    }

    string filePath = openFileDialog.FileName;
    FileInfo fileInfo = new FileInfo(filePath);

    using (ExcelPackage package = new ExcelPackage(fileInfo))
    {

        ExcelWorksheet worksheet = package.Workbook.Worksheets[0];
        int rowCount = worksheet.Dimension.Rows;

        // Start the main transaction once
        using (Transaction trans = new Transaction(doc, "Add Parameters from Excel"))
        {
            if (trans.Start() == TransactionStatus.Started)
            {




                // Process each row in the Excel sheet
                for (int row = 2; row <= rowCount; row++) // Assuming first row is headers
                {
                    string serialNumber = worksheet.Cells[row, 6].Text;

                    if (!string.IsNullOrEmpty(serialNumber))
                    {
                        Element element = FindElementBySerialNumber(doc, serialNumber);

                        if (element != null && element.Category.AllowsBoundParameters)
                        {
                            // Bind and apply parameters for this specific element
                            for (int col = 1; col <= 5; col++) // Assuming parameters are in columns 1 to 5
                            {
                                string paramName = worksheet.Cells[1, col].Text;  // Get parameter name from header row
                                string paramValue = worksheet.Cells[row, col].Text; // Get parameter value for this element

                                if (!string.IsNullOrEmpty(paramName) && !string.IsNullOrEmpty(paramValue))
                                {
                                    // Bind the parameter dynamically to the element's category
                                    BindSharedParameterToProject(commandData.Application, doc, paramName, element.Category);

                                    // Assign the parameter value to the element
                                    Parameter param = element.LookupParameter(paramName);
                                    if (param != null && !param.IsReadOnly)
                                    {
                                        param.SetValueString(paramValue.Trim());
                                    }
                                }
                            }
                        }
                    }
                }

                // Commit the transaction after all elements are processed
                trans.Commit();
            }
            else
            {
                trans.RollBack();
            }
        }
    }
    // Show a confirmation message to the user
    TaskDialog.Show("Success", "Parameters have been successfully created and assigned.");

    return Result.Succeeded;
}

and here’s my binding method for adding new shared parameter :

private void BindSharedParameterToProject(UIApplication uiApp, Document doc, string paramName, Category elementCategory)
{
    // Check if the category allows bound parameters
    if (!elementCategory.AllowsBoundParameters)
    {
        TaskDialog.Show("Category Error", $"The category '{elementCategory.Name}' does not allow bound parameters.");
        return; // Skip binding if the category doesn't support parameters
    }

    // Ensure a shared parameter file is set
    if (string.IsNullOrEmpty(uiApp.Application.SharedParametersFilename))
    {
        // If no shared parameter file is set, create one
        string sharedParamsFile = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments), "RevitSharedParams.txt");
        uiApp.Application.SharedParametersFilename = sharedParamsFile;
    }

    DefinitionFile defFile = uiApp.Application.OpenSharedParameterFile();
    if (defFile == null)
    {
        throw new InvalidOperationException("No shared parameter file is set or accessible.");
    }

    DefinitionGroup defGroup = defFile.Groups.get_Item("Orbits Parameters") ?? defFile.Groups.Create("Orbits Parameters");

    // Check if the parameter already exists in the group
    Definition paramDef = defGroup.Definitions.get_Item(paramName);
    if (paramDef == null)
    {
        ForgeTypeId dataType = SpecTypeId.String.Text;  // Assuming parameter type is string
        ExternalDefinitionCreationOptions options = new ExternalDefinitionCreationOptions(paramName, dataType);
        paramDef = defGroup.Definitions.Create(options);
    }

    // Bind the parameter to the element's specific category (dynamically)
    CategorySet categorySet = new CategorySet();
    categorySet.Insert(elementCategory); // Bind to the specific element's category

    // Use instance binding (assuming you want instance parameters)
    InstanceBinding instanceBinding = uiApp.Application.Create.NewInstanceBinding(categorySet);
    BindingMap bindingMap = doc.ParameterBindings;

    ForgeTypeId groupTypeId = GroupTypeId.General;
    if (!bindingMap.Contains(paramDef))
    {
        bindingMap.Insert(paramDef, instanceBinding, groupTypeId); // Insert to bind the parameter
    }
    else
    {
        bindingMap.ReInsert(paramDef, instanceBinding, groupTypeId); // ReInsert to ensure the binding is correct
    }
}

i tried to make the commit ater each element i add the paramter to it but still it just add the parameters only to the last element in the list

i tried to do sub-transaction also tried to do transaction after each element but didn’t work