Hello Dynamo Friends
I have some problems at understanding the code mentioned in another thread.
The code checks if a parameter (binding) already exists in the project.
If the parameter binding exists, it will be deleted and then created again 
I want the code to just stop if the parameter already exists. I´m obviously missing something here, can someone please explain why this deleting of the binding is necessary?
Happy about any advice 
kind regards!
#Inspired by an archilab node, by Konrad Sobon
#Modifications by Alban de Chasteigner 2020
# test fix by Cyril Poupin for Revit 2022+
#twitter : @geniusloci_bim
#geniusloci.bim@gmail.com
#https://github.com/albandechasteigner/GeniusLociForDynamo
import clr
clr.AddReference("RevitAPI")
import Autodesk
from Autodesk.Revit.DB import *
clr.AddReference("RevitServices")
import RevitServices
from RevitServices.Persistence import DocumentManager
from RevitServices.Transactions import TransactionManager
doc = DocumentManager.Instance.CurrentDBDocument
uiapp = DocumentManager.Instance.CurrentUIApplication
app = uiapp.Application
version=int(app.VersionNumber)
import System
from System.Collections.Generic import List
from System import Guid
_paramName = IN[0] if isinstance(IN[0],list) else [IN[0]]
_groupName = IN[1]
parameterTypes = IN[2] if isinstance(IN[2],list) else [IN[2]]
parameterGroups = IN[3] if isinstance(IN[3],list) else [IN[3]]
_instance = IN[4] if isinstance(IN[4],list) else [IN[4]]
_visible = IN[5] if isinstance(IN[5],list) else [IN[5]]
guids = IN[6] if isinstance(IN[6],list) else [IN[6]]
_categories = IN[7] if isinstance(IN[7],list) else [IN[7]]
paramTypes_len = len(parameterTypes) == 1
paramGroups_len = len(parameterGroups) == 1
instance_len = len(_instance) == 1
visible_len = len(_visible) == 1
guid_len = len(guids) == 1
if version < 2022:
_paramGroup = [System.Enum.Parse(Autodesk.Revit.DB.BuiltInParameterGroup, parameterGroup) if isinstance(parameterGroup, basestring) else parameterGroup for parameterGroup in parameterGroups]
_paramType = [System.Enum.Parse(Autodesk.Revit.DB.ParameterType, parameterType) if isinstance(parameterType, basestring) else parameterType for parameterType in parameterTypes]
else:
# parameter Group
propGP_infos = clr.GetClrType(GroupTypeId).GetProperties()
dictGrp_forgeTypeId = {p.Name : p.GetGetMethod().Invoke(None, None) for p in propGP_infos}
_paramGroup = [dictGrp_forgeTypeId.get(parameterGroup) for parameterGroup in parameterGroups if isinstance(parameterGroup, basestring)]
# compute a dictionnary of all SpecTypeId {SpecTypeId Name : SpecTypeId}
dict_forgeTypeId = {}
#
for specTypeId_class in [clr.GetClrType(SpecTypeId), clr.GetClrType(SpecTypeId.Boolean), clr.GetClrType(SpecTypeId.Int), clr.GetClrType(SpecTypeId.String)]:
prop_infos = specTypeId_class.GetProperties()
dict_temp_forgeTypeId = {p.Name : p.GetGetMethod().Invoke(None, None) for p in prop_infos}
dict_forgeTypeId = dict(dict_forgeTypeId, **dict_temp_forgeTypeId)
#
_paramType=[dict_forgeTypeId.get(parameterType) for parameterType in parameterTypes if isinstance(parameterType, basestring)]
_guid = [Guid(guid) if isinstance(guid, basestring) else guid for guid in guids]
def IsEqualTo_ParameterType(para_def, paraType):
"""
check if ParameterType of a defintion is Equal to a other ParameterType (or SpecTypeId)
"""
if version < 2022:
return para_def.ParameterType == paraType
else:
return para_def.GetDataType() == paraType
def ParamBindingExists(_doc, _paramName, _paramType):
map = doc.ParameterBindings
iterator = map.ForwardIterator()
iterator.Reset()
while iterator.MoveNext():
if iterator.Key != None and iterator.Key.Name == _paramName and IsEqualTo_ParameterType(iterator.Key, _paramType):
paramExists = True
break
else:
paramExists = False
return paramExists
def RemoveParamBinding(_doc, _paramName, _paramType):
map = doc.ParameterBindings
iterator = map.ForwardIterator()
iterator.Reset()
while iterator.MoveNext():
if iterator.Key != None and iterator.Key.Name == _paramName and IsEqualTo_ParameterType(iterator.Key, _paramType):
definition = iterator.Key
break
message = None
if definition != None:
map.Remove(definition)
message = "Success"
return message
def addParam(doc, _paramName, _paramType, _visible, _instance, _guid, _groupName, _paramGroup,_categories):
message = None
if ParamBindingExists(doc, _paramName, _paramType):
if not RemoveParamBinding(doc, _paramName, _paramType) == "Success":
message = "Param Binding Not Removed Successfully"
else:
message = None
group = app.OpenSharedParameterFile().Groups.get_Item(_groupName)
if group == None:
group = file.Groups.Create(_groupName)
if group.Definitions.Contains(group.Definitions.Item[_paramName]):
_def = group.Definitions.Item[_paramName]
else:
opt = ExternalDefinitionCreationOptions(_paramName, _paramType)
opt.Visible = _visible
if _guid != None:
opt.GUID = _guid
_def = group.Definitions.Create(opt)
cats=app.Create.NewCategorySet()
builtInCategories=[doc.Settings.Categories.get_Item(System.Enum.ToObject(BuiltInCategory, _category.Id)) for _category in _categories]
[cats.Insert(builtInCategory) for builtInCategory in builtInCategories]
if _instance:
bind=app.Create.NewInstanceBinding(cats)
else:
bind=app.Create.NewTypeBinding(cats)
param = doc.ParameterBindings.Insert(_def, bind, _paramGroup)
return message
TransactionManager.Instance.EnsureInTransaction(doc)
try:
file = app.OpenSharedParameterFile()
except:
message = "No Shared Parameter file found."
pass
for number in xrange(len(_paramName)):
t = 0 if paramTypes_len else number
g = 0 if paramGroups_len else number
i = 0 if instance_len else number
v = 0 if visible_len else number
d = 0 if guid_len else number
message = addParam(doc, _paramName[number], _paramType[t], _visible[v], _instance[i], _guid[d], _groupName, _paramGroup[g],_categories)
TransactionManager.Instance.TransactionTaskDone()
if message == None:
OUT = "Success"
else:
OUT = message