void ITransactedModelEvent.Rollback(ModelTransaction transaction)
{
Prepare(transaction);
ModelEventScope.Perform(() =>
{
ModelContext context = Instance.Type.Context;
ModelInstanceList list = Instance.GetList(Property);
if (Added != null)
{
foreach (ModelInstance item in Added)
{
list.Remove(item);
}
}
if (Removed != null)
{
foreach (ModelInstance item in Removed)
{
list.Add(item);
}
}
});
}
/// <summary>
/// Enumerates over the set of instances represented by the current step.
/// </summary>
/// <param name="instance"></param>
/// <returns></returns>
public IEnumerable <ModelInstance> GetInstances(ModelInstance instance)
{
// Exit immediately if the property is not valid for the specified instance
if (!DeclaringType.IsInstanceOfType(instance))
{
throw new ArgumentException("The current property is not valid for the specified instance.");
}
// Return each instance exposed by a list property
if (IsList)
{
ModelInstanceList children = instance.GetList(this);
if (children != null)
{
foreach (ModelInstance child in children)
{
yield return(child);
}
}
}
// Return the instance exposed by a reference property
else
{
ModelInstance child = instance.GetReference(this);
if (child != null)
{
yield return(child);
}
}
}
public IModelPropertySource GetSource(ModelInstance root, Func <ModelInstance, ModelReferenceProperty, int, bool> whenNull, Action <ModelInstance, ModelReferenceProperty, int, ModelInstance> whenNotNull)
{
// Return the source type for static paths
if (IsStatic)
{
return(ModelContext.Current.GetModelType(SourceType));
}
//walk the path performing whenNull if an entity is null
//if an entity is null and whenNull returns false
//then exit out of SetValue returning false
foreach (SourceStep step in this.steps.Take(this.steps.Length - 1))
{
ModelReferenceProperty stepProp = (ModelReferenceProperty)step.DeclaringType.Properties[step.Property];
if (stepProp.IsList)
{
ModelInstanceList list = root.GetList(stepProp);
if (list.Count < step.Index + 1 && (whenNull == null || !whenNull(root, stepProp, step.Index)))
{
return(null);
}
var item = list[step.Index];
if (whenNotNull != null)
{
whenNotNull(root, stepProp, step.Index, item);
}
root = item;
}
else
{
if (root.GetReference(stepProp) == null && (whenNull == null || !whenNull(root, stepProp, step.Index)))
{
return(null);
}
else
{
//advance to the next step in the chain.
var child = root.GetReference(step.Property);
if (whenNotNull != null)
{
whenNotNull(root, stepProp, step.Index, child);
}
root = child;
}
}
}
return(root);
}
/// <summary>
/// Enumerates over the set of instances represented by the current step.
/// </summary>
/// <param name="instance"></param>
/// <returns></returns>
public IEnumerable <ModelInstance> GetInstances(ModelInstance instance)
{
// Stop loading if the step is null or represents a value
if (Property is ModelValueProperty || !((ModelReferenceProperty)Property).DeclaringType.IsInstanceOfType(instance))
{
yield break;
}
// Cast the property to the correct type
var reference = (ModelReferenceProperty)Property;
// Return each instance exposed by a list property
if (reference.IsList)
{
ModelInstanceList children = instance.GetList(reference);
if (children != null)
{
foreach (ModelInstance child in instance.GetList(reference))
{
if (Filter == null || Filter.IsInstanceOfType(child))
{
yield return(child);
}
}
}
}
// Return the instance exposed by a reference property
else
{
ModelInstance child = instance.GetReference(reference);
if (child != null && (Filter == null || Filter.IsInstanceOfType(child)))
{
yield return(child);
}
}
}