protected override bool ConditionApplies(ModelInstance root)
{
var value = root[Property];
// Exit immediately if the target property has a value
if (RequiredValue == null && (value != null &&
(!(Property is ModelReferenceProperty) || !Property.IsList || root.GetList((ModelReferenceProperty)Property).Count > 0)))
{
return(false);
}
// If the required value is specified then the value must equal the required value
var requiredValueCondition = RequiredValue == null || !RequiredValue.Equals(value);
// Invoke the ModelExpression if it exists
if (RequiredExpression != null)
{
try
{
return((bool)RequiredExpression.Invoke(root) && requiredValueCondition);
}
catch
{
return(false);
}
}
// If the value to compare is null, then evaluate whether the compare source has a value
else if (CompareValue == null)
{
return((CompareOperator == CompareOperator.Equal ? !compareSource.HasValue(root) : compareSource.HasValue(root)) && requiredValueCondition);
}
// Otherwise, perform a comparison of the compare source relative to the compare value
bool?result = CompareRule.Compare(compareSource.GetValue(root), CompareOperator, CompareValue);
return(result.HasValue && result.Value && requiredValueCondition);
}
