Check if a Category contains any element

[mahshid.motie]

Hi 🙂

From this post (https://thebuildingcoder.typepad.com/blog/2010/05/categories.html), thanks to Jeremmy, I managed to get the list of all categories in my model. However, there are many categories which no element belongs to them. I want to have only the list of categories (or sub categories) which contain at least one element. How can I get this list?

Many thanks in advance 🙂

[recepagah12]

You can iterate the categories in the loop and check if null or size >0. Then you can remove them if you want.

I hope this helps,

Recep.

[mahshid.motie]

Hi recepagah 🙂

Thanks for your answer. Here is my code:

//get UIDocument
UIDocument uidoc = commandData.Application.ActiveUIDocument;

//get document
Document doc = uidoc.Document;

try
{

Categories categories = doc.Settings.Categories;

int n = categories.Size;

StringBuilder CategoryInformation = new StringBuilder();
CategoryInformation.Append(n + "," + "Categories and their parents");

foreach (Category c in categories)
{
Category p = c.Parent;

CategoryInformation.Append("\n" + c.Name + "," + c.Id + "," + "parent:" + (null == p ? "<none>" : p.Name));

}
TaskDialog.Show("Revit", CategoryInformation.ToString());

return Result.Succeeded;
}

catch (Exception e)
{
message = e.Message;
return Result.Failed;
}

I tried to use your advice but didnt figure out to try it on which parameter of categories? I tried adding c.size, but it doesnt exists.

[jeremytammik · Accepted solution]

For each category, create a filtered element collector and retrieve the count of elements that match the category and are not types.

If this advice is not clear to you, please work through the getting started material before asking any further questions:

https://thebuildingcoder.typepad.com/blog/about-the-author.html#2

[mahshid.motie]

Thanks a lot. This method works 🙂

[mahshid.motie]

But can you explain why it should not be a type?

[jeremytammik]

You need to know whether element type should be allowed or not.

It depends on your needs.

If you do not know, you should stop programming Revit right here and now and learn about the difference between types and instances first, before taking a single further step.

Here are some hints:

https://forums.autodesk.com/t5/revit-api-forum/importinstance-like-in-dynamo/m-p/8741697