Create a new project parameter only if it does not already exist

How do I create a new project parameter via Dynamo only if it does not exist in the current project?
Is there a way to set up an If condition?

Try Element.ParameterExists from Clockwork

you can try something like this:

in List.ContainsItem - ITEM just put string that you are looking for.

How do I pass a null value or prevent creating a new parameter?

You just need to use Boolean result from List.ContainsItem on Names and Parameter Types (everything that is list).

Is this problem solved? I don’t see how to connect the boolean result list to the node Parameter.CreateProjectParameter

You need to filter Parameter Names with your boolean.

OK it works! Thanks.

Just mark it as solution. TY :slight_smile:

I think it’s more effective to make my print screen appear as solution than the one above. As beginner user, I needed some minutes to figure out how to connect it with Parameter.CreateProjectParameter. Thanks for the solution anyway!