Question

Here’s the current code I have got

private void recalculateRRange(Excel.Range UsedRange)
{
    Excel.Range currentRRange = null, firstRRange = null;
    currentRRange = (Excel.Range)UsedRange.Find("#HERE#", Type.Missing, Excel.XlFindLookIn.xlValues, Excel.XlLookAt.xlPart, Excel.XlSearchOrder.xlByRows, Excel.XlSearchDirection.xlNext, false, Type.Missing, Type.Missing);
    while (currentRRange != null)
    {
        if (firstRRange == null)
        {
            firstRRange = currentRRange;
        }
        else if (currentRRange.get_Address(Type.Missing, Type.Missing, Excel.XlReferenceStyle.xlA1, Type.Missing, Type.Missing) == firstRRange.get_Address(Type.Missing, Type.Missing, Excel.XlReferenceStyle.xlA1, Type.Missing, Type.Missing))
        {
            break;
        }
        //force current range to recalculate
        currentRRange.Calculate();

        currentRRange = (Excel.Range)UsedRange.FindNext(currentRRange);

    }
}

The above method is used to find the cells that marked as #HERE# and to force this cell to recalculate so we can get the updated results.

I managed to get this code working a day ago but somehow it’s not working now. I guess that code is somewhat buggy anyway as I have been able to capture the exception just one time. I wonder if there’s any better way to implement it?

Exception captured:

Exception from HRESULT: 0x800AC472
at System.RuntimeType.ForwardCallToInvokeMember(String memberName, BindingFlags flags, Object target, Int32[] aWrapperTypes, MessageData& msgData)
at Microsoft.Office.Interop.Excel.Range.Calculate()

I don’t know whether or not it meant something. My best guess is that probably something prevents currentRRange from calling Calculate().

Answer 1

The error you get means VBA_E_IGNORE which in turn means that something/someone is running/interacting on that sheet… this could be a user and/or some complex calculation.

You should set Visible = false on the Excel application object and wait a little while after selecting the Range and retry the Calculate call when you receive this error…

Another point: you should avoid accessing the Excel application object from multiple threads.