public void AssociateFamilyParameter(){
			UIDocument uidoc = this.ActiveUIDocument;
			Document doc = uidoc.Document;
			
			Reference sel = uidoc.Selection.PickObject(ObjectType.Element, "Select element");
			
			Element ele = doc.GetElement(sel);
			
			Parameter eleMatParam = ele.get_Parameter(BuiltInParameter.MATERIAL_ID_PARAM);
			
			FamilyManager fm = doc.FamilyManager;
			
			ICollection<ElementId> materials = new FilteredElementCollector(doc).OfCategory(BuiltInCategory.OST_Materials).ToElementIds();
			
			FamilyParameter famparam = fm.get_Parameter(BuiltInParameter.MATERIAL_ID_PARAM);
			
			using (Transaction t = new Transaction(doc, "Add Param")){
				t.Start();
				
				FamilyParameter p = fm.AddParameter("My Structural Material", BuiltInParameterGroup.PG_GENERAL, ParameterType.Material,true);
			
				doc.FamilyManager.Set(p, materials.First());

				fm.AssociateElementParameterToFamilyParameter(eleMatParam, p);

				
				t.Commit();
			}
			
		}