public void SetValue(string key, string value)
        {
            PdfAcroForm  form  = PdfAcroForm.GetAcroForm(pdfDoc, true);
            var          i     = form.GetDefaultAppearance();
            var          i2    = form.GetDefaultJustification();
            var          i3    = form.GetDefaultResources();
            PdfFormField field = form.GetFormFields()[key];

            if (field is PdfTextFormField)
            {
                PdfTextFormField pdfTextFormField = (PdfTextFormField)field;
                ///pdfTextFormField.SetDefaultAppearance("/Titillium 6 Tf 0 g");
                if (pdfTextFormField.GetFieldName().GetValue().Contains("Beurteilung"))
                {
                    pdfTextFormField.SetDefaultAppearance("/Helv 6 Tf 0 g");
                }

                pdfTextFormField.SetValue(value);
            }
            else
            {
                field.SetValue(value);
            }
        }