Writing Validation Rules

A validator is made from validation rules; each rule represents an independent piece of logic that performs a pass/fail test. In CSF.Validation, a rule is a .NET class which implements at least one of the two rule interfaces. A single rule class may implement both interfaces and/or may implement the same interface for several generic types if appropriate.

Rules overview

Both rule interfaces define the method GetResultAsync (with parameters appropriate to the corresponding generic rule interface). This method performs a single validation test and should usually return either a pass/fail result or should throw an exception.

In more advanced scenarios, rules may supplement their result with a dictionary of arbitrary data. This is useful when the validation result would benefit from some further contextual information.

You are also encouraged to read this advice regarding best practices for writing validation rules.