Beginner's Guide to Selecting Element With The Revit API

This video will help you understand how to select elements in your current Revit document through the Revit API.  Programmatically select a single model element or select multiple model elements, then looping through each one to create a list of elements "List<Element>".

Tips:

• Using Linq - A Microsoft query language.  I use a lambda expression which is simpler than using an "if" statement and going through the list. 
• Using text - A string builder which will allow us to append strings to the end of the list.  I convert it back to a regular string using the “ToString()”

Sample Code

            UIApplication uiapp = commandData.Application;

            UIDocument uidoc = uiapp.ActiveUIDocument;

            Application app = uiapp.Application;

            Document doc = uidoc.Document;

            IList<Reference> pickedObjs = uidoc.Selection.PickObjects(ObjectType.Element, "Select elements");

            List<ElementId> ids = (from Reference r in pickedObjs select r.ElementId).ToList();

            using (Transaction tx = new Transaction(doc))

            {

                StringBuilder sb = new StringBuilder();

                tx.Start("transaction");

                if (pickedObjs != null && pickedObjs.Count > 0)

                {

                    foreach (ElementId eid in ids)

                    {

                        Element e = doc.GetElement(eid);

                        sb.Append("\n" + e.Name);

                    }

                    TaskDialog.Show("title :) ", sb.ToString());

                }

                tx.Commit();

            }

Sample Code 

            UIApplication uiapp = commandData.Application;

            UIDocument uidoc = uiapp.ActiveUIDocument;

            Application app = uiapp.Application;

            Document doc = uidoc.Document;

            Reference reference = uidoc.Selection.PickObject(ObjectType.Element);

            Element element = uidoc.Document.GetElement(reference);

            using (Transaction tx = new Transaction(doc))

            {

                TaskDialog.Show("title :) ", element .Name);

             }

            tx.Commit();

            }