private static void UnregisterFromLists(object recipient, Dictionary <Type, List <WeakActionAndToken> > lists)
{
if (recipient == null ||
lists == null ||
lists.Count == 0)
{
return;
}
lock (lists)
{
foreach (Type messageType in lists.Keys)
{
foreach (WeakActionAndToken item in lists[messageType])
{
WeakEventAction weakAction = item.Action;
if (weakAction != null &&
recipient == weakAction.Target)
{
weakAction.MarkForDeletion();
}
}
}
}
}
/// <summary>
/// Registers a recipient for a type of message TMessage.
/// The action parameter will be executed when a corresponding
/// message is sent. See the receiveDerivedMessagesToo parameter
/// for details on how messages deriving from TMessage (or, if TMessage is an interface,
/// messages implementing TMessage) can be received too.
/// <para>Registering a recipient does not create a hard reference to it,
/// so if this recipient is deleted, no memory leak is caused.</para>
/// </summary>
/// <typeparam name="TMessage">The type of message that the recipient registers
/// for.</typeparam>
/// <param name="recipient">The recipient that will receive the messages.</param>
/// <param name="token">A token for a messaging channel. If a recipient registers
/// using a token, and a sender sends a message using the same token, then this
/// message will be delivered to the recipient. Other recipients who did not
/// use a token when registering (or who used a different token) will not
/// get the message. Similarly, messages sent without any token, or with a different
/// token, will not be delivered to that recipient.</param>
/// <param name="receiveDerivedMessagesToo">If true, message types deriving from
/// TMessage will also be transmitted to the recipient. For example, if a SendOrderMessage
/// and an ExecuteOrderMessage derive from OrderMessage, registering for OrderMessage
/// and setting receiveDerivedMessagesToo to true will send SendOrderMessage
/// and ExecuteOrderMessage to the recipient that registered.
/// <para>Also, if TMessage is an interface, message types implementing TMessage will also be
/// transmitted to the recipient. For example, if a SendOrderMessage
/// and an ExecuteOrderMessage implement IOrderMessage, registering for IOrderMessage
/// and setting receiveDerivedMessagesToo to true will send SendOrderMessage
/// and ExecuteOrderMessage to the recipient that registered.</para>
/// </param>
/// <param name="action">The action that will be executed when a message
/// of type TMessage is sent.</param>
public virtual void Register <TMessage>(
object recipient,
object token,
bool receiveDerivedMessagesToo,
Action <TMessage> action)
{
lock (_registerLock)
{
Type messageType = typeof(TMessage);
Dictionary <Type, List <WeakActionAndToken> > recipients;
if (receiveDerivedMessagesToo)
{
if (_recipientsOfSubclassesAction == null)
{
_recipientsOfSubclassesAction = new Dictionary <Type, List <WeakActionAndToken> >();
}
recipients = _recipientsOfSubclassesAction;
}
else
{
if (_recipientsStrictAction == null)
{
_recipientsStrictAction = new Dictionary <Type, List <WeakActionAndToken> >();
}
recipients = _recipientsStrictAction;
}
lock (recipients)
{
List <WeakActionAndToken> list;
if (!recipients.ContainsKey(messageType))
{
list = new List <WeakActionAndToken>();
recipients.Add(messageType, list);
}
else
{
list = recipients[messageType];
}
var weakAction = new WeakEventAction <TMessage>(recipient, action);
var item = new WeakActionAndToken
{
Action = weakAction,
Token = token
};
list.Add(item);
}
}
Cleanup();
}