topic Re: Element Returns null in Revit API Forum

Element Returns null

mohd.fadel — Wed, 05 May 2021 21:05:38 GMT

Hello,

I don't know what i'm missing here.. I'm trying to set the value of a parameter after i retrieve the element from a set of ids. However, the element is returning null and i'm a receiving an error "Object reference not set to an instance of an object"

Element elem = activeDoc.GetElement("224716") as Element;

Parameter RW_CV1 = elem.LookupParameter("RW_CV-1");
RW_CV1.Set("New");
RW_CV1.SetValueString("New");

please note that 224716 is a valid id of the element. I can double check that using select by id.

Any help is appreciated.

Mohamed.

Re: Element Returns null

jeremy_tammik — Thu, 06 May 2021 09:36:23 GMT

So, you are saying that 224716 is the valid integer value of the element id.

That is good to know.

Please note that the string "224716" is something completely different. A string is not a number, nor an element id.

In this case, however, a string might very well be a Revit unique id.

And, lo and behold, the GetElement method provides three overloads, one taking an element id, another a string-valued unique id:

https://www.revitapidocs.com/2021.1/8760be74-50fd-6809-aec6-3cb168d03ea5.htm

To make use of your integer-valued element id, you need to convert the number (not the string) to an ElementId object and pass in that to GetElement. Since this is demonstrated in a numerous different places, I am sure you have already solved this problem yourself long before I finished typing this.

Re: Element Returns null

mohd.fadel — Thu, 06 May 2021 19:15:31 GMT

Thank you Jeremy. That did it.