topic Re: calculate field fails in ArcObjects SDK Questions

calculate field fails

JustinShepard — Sun, 12 Dec 2021 06:28:56 GMT

I have an IFeatureClass created in my code and I have added a new field to it. I'm stuck on calculating values for the new field. I've tried using CalculateField and ICalculator but I get errors from both (see code below). Any suggestions?

IFeatureClass classifiedPolygons_IFC

IFieldEdit2 field

     
/*
* Error HRESULT E_FAIL has been returned from a call to a COM component.
* I've also tried casting the IFeatureClass to ITable
*/
CalculateField calculateField = new CalculateField()
{
    in_table = classifiedPolygons_IFC,
    field = classifiedPolygons_IFC.Fields.Field[classifiedPolygons_IFC.Fields.FindField(field.Name)],
    expression = "Calc Val",
    expression_type = "Python"
};
Geoprocessor gp = new Geoprocessor();
gp.Execute(calculateField, null);

/*
* "Retrieving the COM class factory for component with CLSID {D676066E-38CA-429A-B846-DA7A8446C52D} failed due to the following error: 80040154 Class not registered (Exception from HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG))."
*/
ICursor updateCursor = classifiedPolygons_IFC.Update(null, false) as ICursor;// table.Update(null, false);
ICalculator calculator = new Calculator()
{
    Cursor = updateCursor,
    Field = field.Name,
    Expression = "Calc Val"
};
calculator.Calculate();
Marshal.FinalReleaseComObject(updateCursor);

Re: calculate field fails

ModyBuchbinder — Thu, 25 Dec 2014 06:13:23 GMT

If
you open an update cursor you should just calculate the values.

Check
the update cursor example (and a few other examples) here: http://resources.arcgis.com/en/help/arcobjects-net/conceptualhelp/0001/0001000001mm000000.htm

Have
fun

Mody

Re: calculate field fails

RichardFairhurst — Thu, 25 Dec 2014 14:49:45 GMT

Calc Val is a string and expression is a string variable, but the string must be quoted twice, once for the actual value in the field calucator, and another time for the string variable. So expression = "Calc Val" won't work, but expression = "'Calc Val'" should work (single quotes inside double quotes work for Python calculations, but not VB Script calculations. For VB Script it would be expression = """Calc Val""").

Re: calculate field fails

JustinShepard — Fri, 26 Dec 2014 05:41:48 GMT

I'm on holiday right now but I'll give it a try on Monday and let you know how it goes. Cheers.

Re: calculate field fails

JustinShepard — Mon, 29 Dec 2014 17:28:46 GMT

Thanks for catching that. I'm sure I'll be posting more questions as I work through creating my first SOE.