Python: Does this titleblock contain this parameter?

[Thatcher]

Hi All,

I am new to Python. I am working on making a dynamo script compatible with older versions of Revit.

My current dilemma: I have a titleblock selected and I want a boolean output about whether a parameter called “KeyplanAreaToggle” exists in the titleblock family.

My latest attempt:

import clr
clr.AddReference(‘RevitServices’)
from RevitServices.Persistence import DocumentManager
from RevitServices.Transactions import TransactionManager

clr.AddReference(‘RevitAPI’)
from Autodesk.Revit.DB import *

Get the current document

doc = DocumentManager.Instance.CurrentDBDocument

Function to check if a parameter exists in a family document

def parameter_exists(family_doc, param_name):
for param in family_doc.FamilyManager.Parameters:
if param.Definition.Name == param_name:
return True
return False

Assuming ‘family_doc’ is the selected family document in Dynamo

family_doc = UnwrapElement(IN[0])
param_name = “KeyplanAreaToggle”

Start a transaction

TransactionManager.Instance.EnsureInTransaction(doc)

Check if the parameter exists

exists = parameter_exists(family_doc, param_name)

End the transaction

TransactionManager.Instance.TransactionTaskDone()

Output the boolean result

OUT = exists

This gives me the warning message:

Thanks in advance for your help.

[Draxl_Andreas]

@Thatcher

paste your code with </>

import clr
clr.AddReference("RevitServices")
from RevitServices.Persistence import DocumentManager
from RevitServices.Transactions import TransactionManager

clr.AddReference("RevitAPI")
from Autodesk.Revit.DB import *

# 📃 Get the current document
doc = DocumentManager.Instance.CurrentDBDocument

# 🚀 Function to check if a parameter exists in a family document
def parameter_exists(family_doc, param_name):
    for param in family_doc.FamilyManager.Parameters:
        if param.Definition.Name == param_name:
            return True
        else:
            return False

# 🤖 Assuming ‘family_doc’ is the selected family document in Dynamo
family_doc = UnwrapElement(IN[0])
param_name = "KeyplanAreaToggle"

# 🔓Start a transaction
TransactionManager.Instance.EnsureInTransaction(doc)

# ❗❗❗ Check if the parameter exists
exists = parameter_exists(family_doc, param_name)

# 🔒End the transaction
TransactionManager.Instance.TransactionTaskDone()

# ✅ Output the boolean result
OUT = exists

i corrected the if statement in the function

[staylor]

Cheap method. This checks to see if the parameter exists in either the family instance or the type in the model.

import clr

clr.AddReference("RevitAPI")
from Autodesk.Revit.DB import *

clr.AddReference('RevitServices')
import RevitServices
from RevitServices.Persistence import DocumentManager
doc = DocumentManager.Instance.CurrentDBDocument

param_name = IN[0]
element = UnwrapElement(IN[1])

element_type = doc.GetElement(element.GetTypeId())

param_exists = element.LookupParameter(param_name)
type_param_exists = element_type.LookupParameter(param_name)

if param_exists or type_param_exists:
	OUT = "true"
else:
	OUT = "false"

[Mike.Buttery]

The warning on the node is that you are passing a list to the function which expects a family document. You code will have to handle this use case.

I’m not sure why you are working with Family Documents?

Here is a title block Family Document parameters vs Element parameters

This is how I would do it in Dynamo

Here’s one way in Python

import clr

clr.AddReference("RevitAPI")
from Autodesk.Revit.DB import *

def param_exists(element, param_name):
    if isinstance(element, Element):
        return bool(element.LookupParameter(param_name))
    
elements = UnwrapElement(IN[0])
param_name = "Volume"

if isinstance(IN[0], list):
    OUT = [param_exists(element, param_name) for element in elements]
else:
    OUT = param_exists(elements, param_name)

Please note you don’t need a transaction as you are only querying the document. If you absolutely need to work with Family Documents please leave a reply and I’ll provide some further assistance.

[Thatcher]

Thank you, @Mike.Buttery Mike.Buttery. It works perfectly.

And thanks for the other responses.
I have a Titleblock element going into IN[0]. I don’t need to get into the titleblock family at this point.

I wanted to let you see my results:

@Draxl_Andreas , It gave a null output and the message - Warning: IronPythonEvaluator.EvaluateIronPythonScript operation failed.
Traceback (most recent call last):
File “”, line 29, in
File “”, line 15, in parameter_exists
AttributeError: ‘List[object]’ object has no attribute ‘FamilyManager’

@staylor , It gave a null output and the message - Warning: IronPythonEvaluator.EvaluateIronPythonScript operation failed.
Traceback (most recent call last):
File “”, line 14, in
AttributeError: ‘List[object]’ object has no attribute ‘GetTypeId’

[staylor]

My bad. I didn’t account for a list of titleblock inputs. Here is corrected code if you want.

import clr

clr.AddReference("RevitAPI")
from Autodesk.Revit.DB import *

clr.AddReference('RevitServices')
import RevitServices
from RevitServices.Persistence import DocumentManager
doc = DocumentManager.Instance.CurrentDBDocument

param_name = IN[0]
element = UnwrapElement(IN[1]) if isinstance(IN[1],list) else [UnwrapElement(IN[1])]

for elem in element:
	element_type = doc.GetElement(elem.GetTypeId())
	param_exists = elem.LookupParameter(param_name)
	type_param_exists = element_type.LookupParameter(param_name)

if param_exists or type_param_exists:
	OUT = "true"
else:
	OUT = "false"

[Thatcher]

Thank you, @staylor