Objects selection by Ironpython(.NET API in Civil3D) in Dynamo

Several ways to select objects According to the type as the result below.

Based on TypeName:

output = []

adoc = Application.DocumentManager.MdiActiveDocument
ed = adoc.Editor


with adoc.LockDocument():
	with adoc.Database as db:
		with db.TransactionManager.StartTransaction() as t:
  			bt = t.GetObject(db.BlockTableId, OpenMode.ForWrite)
  			btr = t.GetObject(bt[BlockTableRecord.ModelSpace], OpenMode.ForWrite)

        rList = []


  			#Get the Lines on Layer"Ramps". TypeName could be "Dbtext", "Line"
  			for objectid in btr:
				obj1 = t.GetObject(objectid, OpenMode.ForRead)
				if obj1.GetType().Name.ToString() == "Line" and obj1.Layer == "Ramps-Side":
						rList.append(str(obj1.Handle))
				else:
  					pass

ed.WriteMessage("Done")

Type of the object

adoc = acapp.DocumentManager.MdiActiveDocument
cdoc = CivilApplication.ActiveDocument
ed = adoc.Editor
# The inputs to this node will be stored as a list in the IN variables.
with adoc.LockDocument():
	with adoc.Database as db:
		with db.TransactionManager.StartTransaction() as t:
			bt = t.GetObject(db.BlockTableId, OpenMode.ForWrite)
			btr = t.GetObject(bt[BlockTableRecord.ModelSpace], OpenMode.ForWrite)


			rList = []


			#Get the Lines on Layer"Ramps"
			for objectid in btr:
				obj1 = t.GetObject(objectid, OpenMode.ForRead)
				if obj1.GetType()==Line and obj1.Layer == "Ramps-Side":
				# or we can use  "obj1.GetType() == clr.GetClrType(Line)" to ensure get the same type by .Net types
					rList.append(str(obj1.Handle))
				else:
					pass

Notes:

if obj1.GetType()==Line and obj1.Layer == "Ramps-Side":
	rList.append((obj1.GetType() is clr.GetClrType(Line))) #result is true

if obj1.GetType()==Line and obj1.Layer == "Ramps-Side":
	rList.append((obj1.GetType() is Line)) #result is false

if obj1.GetType()==Line and obj1.Layer == "Ramps-Side":
	rList.append((obj1.GetType() == Line)) #result is True

Select via the class of the object and we donot need to get the object.

adoc = acapp.DocumentManager.MdiActiveDocument
cdoc = CivilApplication.ActiveDocument
ed = adoc.Editor
# The inputs to this node will be stored as a list in the IN variables.
with adoc.LockDocument():
	with adoc.Database as db:
		with db.TransactionManager.StartTransaction() as t:
			bt = t.GetObject(db.BlockTableId, OpenMode.ForWrite)
			btr = t.GetObject(bt[BlockTableRecord.ModelSpace], OpenMode.ForWrite)


			rList = []


			#Get the Lines on Layer"Ramps"
			for objectid in btr:
				obj1 = t.GetObject(objectid, OpenMode.ForRead)
				if (obj1.ObjectId.ObjectClass)==(RXClass.GetClass(Line)) and obj1.Layer == "Ramps-Side":
					rList.append(str(obj1.Handle))
				else:
					pass