See the Validate
function and the ValidationPolicy property for details of
how this property is determined.
Note that it is possible for a signature to be untrusted but
still PAdES compliant.
For example if a document was signed a decade ago it might no
longer be possible to validate the trust chain so it would be
However PAdES Long Term Validation (LTV) signatures embedded in
the document might provide evidence that the signature had been
compliant. If those the LTV signatures are trusted, by impllcation
the signature itself is still trusted.
This type of situation is indicated by an IsTrusted value of
false and a ComplaincePades which
is not None.