test.cs

byte[] document;
	
using (TXTextControl.ServerTextControl tx = new TXTextControl.ServerTextControl()) {
  tx.Create();
  tx.Load("App_Data/vaccination_form.tx", TXTextControl.StreamType.InternalUnicodeFormat);

  using (TXTextControl.DocumentServer.MailMerge mm =
    new TXTextControl.DocumentServer.MailMerge()) {
    mm.TextComponent = tx;
    mm.FormFieldMergeType = TXTextControl.DocumentServer.FormFieldMergeType.Preselect;
    mm.RemoveEmptyFields = false;

    // pre-select form fields with known data and merge
    // data into merge fields
    mm.MergeObject(data);
  }

  tx.Save(out document, TXTextControl.BinaryStreamType.InternalUnicodeFormat);
}