To modify the arrow head, you need to set the block table record object id of the block you want to see as the arrow head to database property “Dimblk”. Below code demonstrates the same. Below code, first loads the "_DOTBLANK" block and then sets the “_DOTBLANK” as the current arrow head. To test the below code, first run the command “setArrowHead” and then try to create a leader/dimension through AutoCAD UI.
static public void setArrowHead()
Document doc = Application.DocumentManager.MdiActiveDocument;
Database db = doc.Database;
using (Transaction tr = db.TransactionManager.StartTransaction())
BlockTable blockTable = tr.GetObject(db.BlockTableId,
OpenMode.ForRead) as BlockTable;
//now set the arrow head.
db.Dimblk = blockTable["_DOTBLANK"];