Resolved. There was my mistake.

[klkl12234]

Resolved. There was my mistake.

Hi, I want to change the value of the Mark parameter.
The other parameters changed the values in the same way
The value of this parameter has not been changed.

using (Transaction transaction = new Transaction(doc))
{

List<Element> ductElementList2 = new FilteredElementCollector(doc)
.OfClass(typeof(Duct))
.ToList<Element>();
foreach (Element duct in ductElementList2)
{

Autodesk.Revit.DB.Parameter setMark = newDuct.LookupParameter("Mark");

OR

Autodesk.Revit.DB.Parameter setMark = duct.get_Parameter(BuiltInParameter.ALL_MODEL_MARK);

bool flag = setMark.SetValueString("CBS"); //flag is false

OR

bool flag2 = setMark.Set("CBS"); //flag2 is true
doc.Regenerate();

if (setMark.IsReadOnly) { ////false
int a = 1;
}

}

}

[klkl12234]

Resolved. There was my mistake.

[architect.bim · Accepted solution]

Hi!

There is no problem to change the "Mark" parameter with Set method. But SetValueString method "...only applies to parameters of value types". That's why it returns False and does not change the value. Use Set method instead!