Validation

• Simple Validation
• More Complex Validation
• Prevalidation
• Pre- and Post-Action Hooks

Simple Validation

To provide validation in Mighty, you have to pass in a subclass of the Validator class.

A simple validator might just be:

public class FilmValidator : Validator
{
    override public void Validate<Film>(dynamic item, Action<object> reportError)
    {
        // bogus validation: isn't valid if rental_duration > 5
        if (item.rental_duration > 5)
        {
            reportError("rental_duration > 5");
        }
    }
}

...

var films = new MightyOrm<Film>(connectionString, "Film", validator: new FilmValidator());

Note how we use dynamic for the item to validate. This means it can hold whatever you can pass in as an input object to Mighty (which is pretty much anything with names and values in it), and importantly is NOT restricted to items of the generic type even for generically typed . If you know you’re only going to pass in items of the generic type, you can simply put a cast in your validator.

More Complex Validation

The Validate method as above does not distinguish between different actions which you might be perfoming (i.e. Save, Insert, Update, Delete). To achieve this, override ValidateForAction(OrmAction action, dynamic item, Action<object> reportError) instead. The default implementation of this directly calls Validate (throwing away its action parameter), but you can change that.

MightyOrm also provides an IsValid(item) method. This always calls ValidateForAction with the action type set to Save (which in turn just calls Validate by default, but you can change that).

Prevalidation

Prevalidation is off by default, but can be enabled by setting the PrevalidationType field of your Validator class. Available values are Off (default), Lazy and Full.

When prevalidation is on, before performing an action on an item or items ValidateForAction(OrmAction action, dynamic item, Action<object> reportError) is called one at a time on each item. With lazy validation this is stopped after the first item to produce an error. With full validation, all errors for all items are accumulated. In either case, if any errors are found then a ValidationException (containing all the errors) is thrown, and no database actions are taken.

Pre- and Post-Action Hooks

More fine-grained control is additionally provided with the bool ShouldPerformAction(dynamic item, OrmAction action) and HasPerformedAction(dynamic item, OrmAction action) methods. ShouldPerformAction lets you determine whether an action on an item should take place (without an exception unless you choose to throw one). HasPerformedAction lets you check the item, or do anything else you need to do, once an action has taken place.