PostValidation or typed validation is the process of validating the typed value after parsing, after the input string has been converted to the DataType. Input provides the PostValidation class for validation rules applied after after converting the string entered by the user to the DataType.

PostValidation allows you to validate the typed Value entered by the user.

The PostValidation class allows you to:

• Check that the value matches one of the values in a pre-defined value list specified in the Values property.
• Test the value to see if it is below a minimum or above a maximum, that is you can test to see if the value belongs to an interval.

  You can even specify multiple intervals of allowed values. The intervals are defined in the Intervals property where you specify minimum and maximum values for each interval, and also whether minimum and maximum values are used or ignored, and whether or not the inequality is strict (minimum/maximum value included).

• Exclude some values using the ValuesExcluded property.
• Perform validation programmatically in the Validating event.

To distinguish between declarative and programmatic validation, use the PostValidation property with two possible values: ValuesAndIntervals and ValidatingEvent. Note that PostValidatingEvent disables automatic validation of values and intervals. Call the ValidateValuesAndIntervals method from the event code if you want to combine event code with values and intervals validation.