public static int ReplaceFormelFelder(ReportDocument rpt, string oldValue, string newValue)
        {
            int iCounter = 0, index = 0;
            bool replace = false;
            string text = string.Empty;
 
            foreach (FormulaFieldDefinition item in rpt.DataDefinition.FormulaFields)
            {
                text = item.Text;
                if (text != null)
                {
                    index = text.IndexOf(oldValue);
 
                    while (index != -1)
                    {
                        iCounter++;
                        replace = true;
 
                        if (text.Length > index + 1)
                            index = text.IndexOf(oldValue,index + 1);
                        else
                            index = -1;
                    }
 
                    if (replace)
                    {
                        item.Text = text.Replace(oldValue,newValue);
                        replace = false;
                    }
                }
            }
 
            return iCounter;
        }