CODEWITHSUNDEEP
c#validationfluentvalidation
johnny 5
johnny 5

Reputation: 20997

FluentValidations Get Propertyname from RuleBuilderOptions

I'm trying to create a custom When Extensions to check if my entity has changes. But I'm having trouble getting the Propertyname, which I need with the instance being validated. 

public static bool WhenHasChanged<T, TProperty>(this IRuleBuilderOptions<T, TProperty> rule)
{
    //I need to get the PropertyValidatorContext from the rule
    PropertyValidatorContext context;
    var instance = (IChangeTrackingObject)context.Instance;

    if (false == instance.GetChangedProperties().ContainsKey(context.PropertyName))
    {
        return true;
    }

    var oldValue = instance.GetChangedProperties().Get(context.PropertyName).OldValue;
    var newValue = context.PropertyValue;

    return (null == oldValue) ? null == newValue : oldValue.Equals(newValue);
}

I need to get the PropertyName being validated and the instance that's being validated, normally these lie within the PropertyValidatorContext is there a way to get the PropertyValidatorContext from the rule?

Upvotes: 1

Views: 1234

Answers (1)

johnny 5
johnny 5

Reputation: 20997

I ended up creating a must extensions in stead so I had access to the property validator context:

private static Func<T, TProperty, PropertyValidatorContext, bool> MustWhenChangedPredicate<T, TProperty>(Func<T, TProperty, PropertyValidatorContext, bool> predicate)
{
    return (t, p, context) =>
    {
        var instance = (IChangeTrackingObject)context.Instance;

        //The type name always prefixes the property
        var propertyName = context.PropertyName.Split(new[] { '.' }, 2).Skip(1).First();

        if (false == instance.GetChangedProperties().ContainsKey(propertyName))
        {
            return true;
        }

        var oldValue = instance.GetChangedProperties().Get(propertyName).OldValue;
        var newValue = context.PropertyValue;

        if (oldValue == null && newValue == null)
        {
            return true;
        }

        if ((oldValue != null && oldValue.Equals(newValue)) ||
               (newValue != null && newValue.Equals(oldValue)))
        {
            return true;
        }

        return predicate(t, p, context);
    };
}

Upvotes: 1

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