In a recent project I had the need to create a new project parameter, and then set the value of it on certain elements. This post
has great information on creating project parameters, however that post along with much of the Autodesk documentation add certain parameters to the CategorySet for the InstanceBinding method, what I wanted to do was add all of them. Unfortunately adding all categories in document.Settings.Categories throws an error as not all categories can have parameters bound.
There is a simple solution to this, only add categories to the CategorySet if they have their AllowsBoundParameters property set to true. It’s an obvious solution once you know this flag is available.
CategorySet categories = app.Application.Create.NewCategorySet();
foreach (Category category in doc.Settings.Categories)