The form fields a signature locks: once it is signed, a change to their values invalidates it. Written as the signature field's lock dictionary and copied into the signature's FieldMDP transform parameters.
public sealed class PdfFieldLockOptions
ISO 32000-2 §12.7.5.5, Tables 235 and 236 (signature field lock dictionary, PDF 1.5; its P, PDF 2.0), and §12.8.2.4,
Table 259 (FieldMDP: "the Action and Fields entries in the transform parameters dictionary shall be copied from the corresponding
fields in the signature field lock dictionary").
kind:method, kind:property, kind:ctor. Press Esc to clear.ActionGets which fields are locked: all of them, those FieldNames names, or all but those.FieldNamesGets the fully qualified names of the fields included or excluded; a name locks the field and every field under it. Empty for All.PermissionsGets the changes the document permits once the signature is signed, or null (the default) to leave them as they are. Permissions can only be narrowed: a value wider than those already in effect is ignored. PDF 2.0.All()Locks every field of the document.Exclude(IEnumerable<String>)Locks every field except those fieldNames names and the fields under them.Include(IEnumerable<String>)Locks the fields fieldNames names, and the fields under them.WithPermissions(Nullable<PdfCertificationPermissions>)Returns this lock with Permissions set.