useTempValueDuringBeforeValueChangedChecking property
whether used a temp value during checking whether value can be changed
if true , a temp value will be displayed during checking ,after checking completed, new value or old value(not allowed to change) will be displayed and temp value will be set to null
recommend to set this param to true if beforeValueChanged will take some time to complete
default is true
Implementation
final bool useTempValueDuringBeforeValueChangedChecking;