Enum ValueAccessExceptionBehaviour

Enumerates the possible behaviours which the validator should take when a value-accessor raises an exception.

Namespace: CSF.Validation.Manifest

Assembly: CSF.Validation.Abstractions.dll

Syntax

public enum ValueAccessExceptionBehaviour

Remarks

Typically, a value-accessor: AccessorFromParent should not raise exceptions. If an exception occurs then it will be impossible to validate this value or any of the values derived from it. The validator has a number of ways in which it can respond to such exceptions.

It is down to implementations of IGetsValueToBeValidated to make use of this behaviour, returning an appropriate instance of an object derived from GetValueToBeValidatedResponse for the value accessor, and whether or not it raises an exception.

There is more information available about these behaviours available in the Handling accessor exceptions article.

When the behaviour TreatAsError is indicated and when a value accessor throws an exception, an implementation of IGetsValueToBeValidated should return an instance of ErrorGetValueToBeValidatedResponse.

This means that the accessor exception will be caught and added to the value-to-be-validated response (above). When a validator is performing validation, an additional validation result (not associated with any rule) should be added to the final results. One such result should be added for each distinct instance of ErrorGetValueToBeValidatedResponse. That result will have a Errored and will indicate that the validation has failed with one or more errors. The result will also contain a reference to the original exception which was thrown by the accessor.

When a value has an error-result in this way, no child values or collection item values should be evaluated from it. Additionally, no rules associated with that value will be executed, nor will any rules for any child values.

Whilst overall validation will fail if an exception is thrown by this behaviour, because of the additional error result, the remaining validation will take place. This means that the consumer of validation will still receive the most comprehensive validation result that is possible, with actual results for any rules which were able to run.

When the behaviour Throw is indicated and when a value accessor throws an exception, an implementation of IGetsValueToBeValidated should throw ValidationException with the original exception contained as the inner exception. This exception will then be thrown by the overall validation framework, so the consumer of validation must take responsibility for catching this validation exception.

When the behaviour Ignore is indicated and when a value accessor throws an exception, an implementation of IGetsValueToBeValidated should return an instance of IgnoredGetValueToBeValidatedResponse.

This means that the accessor exception will be caught but ignored. When a validator is performing validation, any value which has an ignored response is simply skipped, along with all of its child/collection values and all associated rules. Value accessors which raise exceptions and which are ignored by this behaviour will not prevent the validation process from succeeding.

The final validation result will include all other results which are unaffected by the value accessor that raised an exception.

Use this behaviour with caution; it is usually a sign of poor object design if accessors such as getters raise exceptions. It is much better to create accessors which do not raise exceptions.

Fields

Name	Description
Ignore	Similar to TreatAsError, but no additional error results will be added, meaning that overall validation may pass.
Throw	Immediately throw the exception caused by the value accessor; validation will be halted with an exception.
TreatAsError	Continue validation of the overall object but add a validation result with an outcome of Errored to the overall validation result. This is the default behaviour.