[Transaction(TransactionMode.Manual)]
    [Regeneration(RegenerationOption.Manual)]
    public class AdskCommandTest : IExternalCommand
    {
        public Result Execute(ExternalCommandData commandData,
            ref string message,
            ElementSet elements)
        {

            var document = commandData.Application.ActiveUIDocument.Document;

            var reference = commandData.Application
                .ActiveUIDocument
                .Selection.PickObject(ObjectType.Element);

            var element = document.get_Element(reference.ElementId);

            foreach (Parameter param in element.Parameters )
            {
                if (param.StorageType == StorageType.Double)
                {
                    try
                    {
                        Debug.Print("Parameter name: {0}\tParameter value (imperial): {1}\t" +
                                "Parameter unit value: {2}\tParameter AsValueString: {3}",
                                param.Definition.Name,
                                param.AsDouble(),
                                param.AsProjectUnitTypeDouble(),
                                param.AsValueString());
                    }
                    catch (Exception ex)
                    {

                        Debug.Print("Parameter name: {0}\tException: {1}", param.Definition.Name, ex.Message);
                    }

                }
            }

        return Result.Succeeded;
}
}