InvalidOperationException at memory location

[Anonymous]

I keep getting this exception when iterating trough a FilteredElementCollector.

Exception thrown at 0x00007FFA03A27788 in Revit.exe:
Microsoft C++ exception: InvalidOperationException at memory location 0x00000099B64FADA8.

If there is a handler for this exception, the program may be safely continued.

[matthew_taylor]

Hi Michal,
Do you delete elements in the iteration?
Post a code snippet. It's a piece of string (length issue) without it.

-Matt

[Anonymous]

The code itself does not delete elements. The families are updated and that does change the element.

        private bool ConvertParameters(Document doc)
        {
            // Load the Elements which will be updated.
            IEnumerable<Element> elements = this.GetAllWoononElements(doc);

            foreach (Element e in elements)
            {
               // what ever, exception iss thrown in the foreach.
            }
        }

 // GetElementsWithGroepParameter returns all the Elements that have the shared parameter
 // KO_Groep. This is a legecy parameter which we know Elements uploaded to WOONON require.
 private IEnumerable<Element> GetAllWoononElements(Document doc)
 {
 var result = new FilteredElementCollector(doc)
 .WhereElementIsNotElementType()
 .Where(q => this.ElementIsWoononElement(q))
 ;

 return result;
 }

        // We use the element name parameter. Don't use the Version parameter, because the
        // project information uses the project parameter as well.
        private bool ElementIsWoononElement(Element e)
        {
            Parameter name = new RevitUtils.ParameterUtil().GetParameterFromFamilyInstanceOrSymbol(WoononParameters.WO_FAMILY_ELEMENT_NAME, e);
            if (name != null && name.HasValue)
                return true;

            Parameter g = new RevitUtils.ParameterUtil().GetParameterFromFamilyInstanceOrSymbol("KO_Groep", e);
            Parameter o = new RevitUtils.ParameterUtil().GetParameterFromFamilyInstanceOrSymbol("KO_Optienummer", e);

            if ((g == null || o == null) || (!g.HasValue || !o.HasValue))
                return false;

            string gs = HParameters.GetParameterValue(g).ToString();
            string os = HParameters.GetParameterValue(o).ToString();

            return 
               !string.IsNullOrWhiteSpace(gs)
            && !string.IsNullOrWhiteSpace(os)
            && !gs.All(c => c == '0')
            && !os.All(c => c == '0')
            ;
        }

[Anonymous]

Ok, i wrapped the foreach in a try catch block and see the exception being what you described:

"- $exception {"The iterator cannot proceed due to changes made to the Element table in Revit's database (typically, This can be the result of an Element deletion)."} Autodesk.Revit.Exceptions.InvalidOperationException"

I guess i'll have to check if the element is valid in ElementIsWoononElement

[Anonymous]

I added isValidObject but the exception is still thrown... Any suggestions?

        private bool ElementIsWoononElement(Element e)
        {
            if (!e.IsValidObject)
                return false;

            Parameter name = new RevitUtils.ParameterUtil().GetParameterFromFamilyInstanceOrSymbol(WoononParameters.WO_FAMILY_ELEMENT_NAME, e);
            if (name != null && name.HasValue)
                return true;

            Parameter g = new RevitUtils.ParameterUtil().GetParameterFromFamilyInstanceOrSymbol("KO_Groep", e);
            Parameter o = new RevitUtils.ParameterUtil().GetParameterFromFamilyInstanceOrSymbol("KO_Optienummer", e);

            if ((g == null || o == null) || (!g.HasValue || !o.HasValue))
                return false;

            string gs = HParameters.GetParameterValue(g).ToString();
            string os = HParameters.GetParameterValue(o).ToString();

            return 
               !string.IsNullOrWhiteSpace(gs)
            && !string.IsNullOrWhiteSpace(os)
            && !gs.All(c => c == '0')
            && !os.All(c => c == '0')
            ;
        }
    }

[Anonymous]

This seems to be exactly what im facing. Iter throug elements, and reload family.

http://adndevblog.typepad.com/aec/2015/03/revitapido-not-add-or-delete-elements-when-iterating-docum...

[matthew_taylor · Accepted solution]

Hi Michal,

Without trying to analyse the issue too much, if you want to proceed in this manner and not have this issue, you could convert the ienumerable to a list and iterate through them in this manner:

for I as integer = 0 to (lst.count - 1)
   Dim elem as element=lst.item(i)
'check your element.
next

It does look like you could simplify your code by using a parametervalueprovider..

-Matt