Hi,
string previousFormula =
Application.ActiveCell.FormulaR1C1.ToString();
Application.ActiveCell.FormulaR1C1 = "=MyUdf()";
Application.ActiveCell.FunctionWizard();
if (!(bool)Application.ActiveCell.FunctionWizard())
{
Application.ActiveCell.FormulaR1C1 = previousFormula;
}
Regards,
Ron