public TValue GetValue(IBehaviorContext context)
{
RequireInitialized();
if (!_cache.HasValue(context))
{
if (_isProviding.GetWithDefault(context, false))
{
// This check is important to avoid the following endless recursion:
// 1. GetValue calls ProvideValue
// 2. ProvideValue directly or indirectly calls GetValue
// 3. GetValue calls Provide value because the cache is not set yet.
// 4. ProvideValue calls GetValue again
//
// The alternative would be to return default(TValue) but it is better
// to avoid this situation altogehter.
throw new InvalidOperationException(EViewModels.ValueAccessedWithinProvideValue);
}
_isProviding.Set(context, true);
TValue value = ProvideValue(context);
_cache.Set(context, value);
_isProviding.Clear(context);
OnInitialize(context);
}
return(_cache.Get(context));
}
public void Revalidate(IBehaviorContext context)
{
ValidationController controller = _validationController.Get(context);
var validationResult = controller.GetResult(_step, context.VM, _property);
bool valueWasInvalid = _invalidValueCache.HasValue(context);
bool valueIsNotInvalidAnymore = validationResult.IsValid;
if (valueWasInvalid && valueIsNotInvalidAnymore)
{
TValue previouslyInvalidValue = _invalidValueCache.Get(context);
_invalidValueCache.Clear(context);
SetValueNext(context, previouslyInvalidValue);
}
else
{
this.PropertyRevalidateNext(context);
}
_resultManager.UpdateValidationResult(context, validationResult);
}
private IEnumerable <TItemSource> GetSourceItems(IBehaviorContext context)
{
if (!_shouldCacheSourceCollection)
{
IEnumerable <TItemSource> source = this.GetValueNext <IEnumerable <TItemSource> >(context);
return(source);
}
if (!_collectionSourceCache.HasValue(context))
{
IEnumerable <TItemSource> source = this.GetValueNext <IEnumerable <TItemSource> >(context);
_collectionSourceCache.Set(context, source);
}
return(_collectionSourceCache.Get(context));
}
