//a button click call back event... private void getEntity_Click(object sender, EventArgs e) { Document doc = Autodesk.AutoCAD.ApplicationServices.Application.DocumentManager.MdiActiveDocument; Editor ed = doc.Editor; Database db = doc.Database; //this - is the modal dialog box. using (EditorUserInteraction UI = ed.StartUserInteraction(this)) { PromptEntityResult entResult = ed.GetEntity(" Select entity"); if (entResult.Status != PromptStatus.OK) return; using (Transaction Tx = db.TransactionManager.StartTransaction()) { DBObject obj = Tx.GetObject(entResult.ObjectId, OpenMode.ForRead); ed.WriteMessage(obj.GetType().Name); Tx.Commit(); } } }