/// <summary>
/// Fires or caches the DataChanged event.
/// </summary>
/// <remarks>
/// Sets <see cref="DataState"/> property to <see cref="DataObjectState.Changed"/> when properties change.
/// </remarks>
protected void DoDataChanged(DataObjectChangeAction action, Guid?propertyId)
{
lock (SyncRoot)
{
// Validate and update state when properties change
if (action == DataObjectChangeAction.Property)
{
if (DataState == DataObjectState.Deleted)
{
throw new InvalidOperationException();
}
DataState = DataObjectState.Changed;
}
// Fire or cache event
if (EventsAreEnabled)
{
// Fire event immediately
OnDataChanged(new DataObjectChangeEventArgs(action, propertyId.HasValue ? new[] { propertyId.Value } : null));
}
else
{
// Cache event...
// Add any chaned property to instance cache
if (propertyId.HasValue && !_instancePropertiesChanged.Contains(propertyId.Value))
{
_instancePropertiesChanged.Add(propertyId.Value);
}
// Process commit or clear instance property change cache depending on action
switch (action)
{
case DataObjectChangeAction.Create:
case DataObjectChangeAction.Update:
// Commit all instance property changes
foreach (var instancePropertyId in _instancePropertiesChanged)
{
if (!_committedPropertiesChanged.Contains(instancePropertyId))
{
_committedPropertiesChanged.Add(instancePropertyId);
}
}
_instancePropertiesChanged.Clear();
// Update is ignored if Create is cached
if ((action == DataObjectChangeAction.Update && !_lastChangeAction.HasValue && _lastChangeAction != DataObjectChangeAction.Create) ||
(action == DataObjectChangeAction.Create))
{
_lastChangeAction = action;
}
break;
case DataObjectChangeAction.Read:
// Clear all non-committed instance property changes on read
_instancePropertiesChanged.Clear();
if (_lastChangeAction.HasValue && _lastChangeAction.Value == DataObjectChangeAction.Property)
{
_lastChangeAction = null;
}
// Read is weakest action
if (!_lastChangeAction.HasValue)
{
_lastChangeAction = action;
}
break;
case DataObjectChangeAction.Delete:
// Clear all instance and committed property changes on delete
_committedPropertiesChanged.Clear();
_instancePropertiesChanged.Clear();
// Delete is strongest action, unless preceded by Create
if (!_lastChangeAction.HasValue || _lastChangeAction.Value != DataObjectChangeAction.Create)
{
// Delete overrides any other value
_lastChangeAction = action;
}
else
{
// Delete after Create cancels out all changes
_committedPropertiesChanged.Clear();
_instancePropertiesChanged.Clear();
_lastChangeAction = null;
}
break;
case DataObjectChangeAction.Property:
// Add property to instance cache
if (!propertyId.HasValue)
{
throw new ArgumentNullException("propertyId");
}
if (!_instancePropertiesChanged.Contains(propertyId.Value))
{
_instancePropertiesChanged.Add(propertyId.Value);
}
// Instance changes only override read
if (!_lastChangeAction.HasValue || _lastChangeAction.Value == DataObjectChangeAction.Read)
{
_lastChangeAction = action;
}
break;
}
}
}
}
/// <summary>
/// Creates an instance with the specified values.
/// </summary>
public DataObjectChangeEventArgs(DataObjectChangeAction action, Guid[] keys)
: base(keys)
{
Action = action;
}
