Sets the field's text (V) and regenerates the normal appearance of every widget to show it.
public void SetValue(string? value)
The text; null removes the value. Line breaks are kept only by a multi-line field.
ISO 32000-2 §12.7.5.3 and §12.7.4.3. The value is stored as a text string in the field's own dictionary (§7.9.2.2), and the
rich text value RV is removed: the text is plain. A password field stores no value (§12.7.5.3, Table 231: a processor
shall never store it) and shows one asterisk per character. Read-only fields are filled too: the flag restricts the user, not
the program.
Appearances are generated as GenerateAppearances() describes, before anything changes, so a failure leaves the
document as it was. When the form also has an XFA resource (Annex K), only the AcroForm value changes and an
XfaDataNotUpdated information diagnostic is recorded: the XFA datasets keep the old value.