topic Re: How to create temporary element? in Revit API Forum

How to create temporary element?

Anonymous — Mon, 27 Jan 2020 07:13:57 GMT

I am trying to get the bounding box of a familyinstance that is created inside a transcation and use it to adjust its parameter in a single transaction. Here is the code.

using (Transaction t = new Transaction(doc, "Create Multiple"))
            {
                t.Start();
                foreach (View view in views)
                {
                    FamilyInstance fi = doc.Create.NewFamilyInstance(point, symbol, view);
                    BoundingBoxXYZ b = fi.get_BoundingBox(doc.ActiveView);
                    fi.LookupParameter(param).Set(b.Max.X.ToString());
                }
                t.Commit();
            }

Re: How to create temporary element?

naveen.kumar.t — Mon, 27 Jan 2020 08:41:22 GMT

Hi @Anonymous ,

you can't set the value of instance parameter before creating the family instance in the project.

Instance parameters are accessible only after creating a family instance inside the project.

Your family instance is created only after the transaction gets completed.

To set the value for a parameter, create one more transaction and set the value.

Re: How to create temporary element?

Anonymous — Mon, 27 Jan 2020 08:48:36 GMT

How do I create another transaction inside a loop and assimilate it in a single transaction to make it undoable once. I am still new in creating subtransactions.

Re: How to create temporary element?

Anonymous — Thu, 30 Jan 2020 08:55:47 GMT

Got it to work. I thought that the error was in my Subtransaction.

Re: How to create temporary element?

ottosson_mathias — Mon, 27 Apr 2020 08:31:03 GMT

@AnonymousI'm having the same question. Can you share your solution?

Thanks!

Re: How to create temporary element?

LTusche1 — Tue, 14 Feb 2023 08:58:12 GMT

Look into TransactionGroups, any transaction that you start and commit within a TransactionGroup, can be rolled back via TransactionGroup.RollBack.

1: Start a TransactionGroup

2: Start regular Transaction

3: Create your element
4: Commit regular Transaction

5: Start another regular Transaction

6: Change parameters

7: Commit regular Transaction

8: Get BoundingBox of your element

9: Rollback the TransactionGroup

Hope this helps.