THPDFWindowsFormDataTransaction.PreparedFieldCount

function PreparedFieldCount: Integer;

Returns the field count from the actual separately loaded candidate after ImportData, ImportDataWithFamilies or FillTypedData succeeds; this is the complete prepared field count, rather than the number of updates

The method polls transaction cancellation; calling it before successful preparation or after TakeCandidate raises EInvalidOpException

Reading the count does not transfer or publish the candidate; use GetPreparedField for zero-based Unicode field values, and commit only after the required publication steps succeed

GetPreparedField, FillTypedData, Transaction class