error when duplicate family symbol !

[hanogkufu]

Please help me! oput of this mistake??

using (Transaction pf = new Transaction(doc))
{
pf.Start("Place Instance");

foreach (PolyLine pLine in pLines)
{
XYZ firstP = pLine.GetOutline().MaximumPoint;

XYZ lastP = pLine.GetOutline().MinimumPoint;

XYZ midP = new XYZ((firstP.X+ lastP.X)/2 , (firstP.Y+ lastP.Y)/2, (firstP.Z + lastP.Z)/2);

IList<XYZ> PLineXYZ = pLine.GetCoordinates();

double l1 = Math.Round(UnitUtils.ConvertFromInternalUnits(PLineXYZ[0].DistanceTo(PLineXYZ[1]), UnitTypeId.Millimeters),0);

double l2 = Math.Round(UnitUtils.ConvertFromInternalUnits(PLineXYZ[1].DistanceTo(PLineXYZ[2]), UnitTypeId.Millimeters), 0);

double Length = l1 > l2 ? l1 : l2;

double Width = l1 < l2 ? l1 : l2;

string symName = Length.ToString() + "x" + Width.ToString() + "x500mm";

FamilySymbol sym = (syms.Where(s => s.Name == symName).FirstOrDefault()) ?? syms[0].Duplicate(symName) as FamilySymbol;

if (!sym.IsActive) sym.Activate();

FamilyInstance instance = doc.Create.NewFamilyInstance(midP, sym, level, StructuralType.Footing);
}
pf.Commit();
}
return Result.Succeeded; 

[Mohamed_Arshad]

Hi @hanogkufu 

    You are trying to duplicate with existing family symbol name. so the error is popping up. The name which you’re using for duplicate must be unique and no family symbol should use that name

Hope this will helps 🙂

[hanogkufu]

Thank for your answer! But i do the condition above, if the "name" existing it must be assign to  the sym before and didn't create new family symbol

[Moustafa_K · Accepted solution]

I think you missed filling back the syms collection with the new created symbol

you need to amend your code to something like this

FamilySymbol sym = (syms.Where(s => s.Name == symName).FirstOrDefault());
if (sym == null)
{
    sym = syms[0].Duplicate(symName) as FamilySymbol;
    syms.Add(sym);
}

[hanogkufu]

@Moustafa_K  yes it is ! thank you so much!