THPDFWindowsFormDataTransaction.PreparedFieldCount

function PreparedFieldCount: Integer;

Returns the field count from the actual separately loaded candidate once ImportData, ImportDataWithFamilies or FillTypedData has succeeded; this is the complete prepared field count, not the number of updates

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

Reading the count neither transfers nor publishes the candidate; use GetPreparedField for zero-based Unicode field values, and commit only once the required publication steps have succeeded

GetPreparedField, FillTypedData, Transaction class