/// <summary>
/// Instantiates a new SingletonProxy object.
/// </summary>
/// <param name="enforcer">The enforcer (first instance of the application) which will receive messages from the new instances of the application.</param>
/// <exception cref="ArgumentNullException">Thrown when the enforcer is null.</exception>
public SingletonProxy(ISingletonEnforcer enforcer)
{
if (enforcer == null)
{
throw new ArgumentNullException("enforcer", "enforcer cannot be null.");
}
_enforcer = enforcer;
}
/// <summary>
/// Instantiates a new SingletonController object to determine whether the application is already running.
/// </summary>
/// <param name="name">The unique name used to identify the application.</param>
/// <param name="enforcer">The ISingletonEnforcer object that will handle messages.</param>
/// <exception cref="System.ArgumentNullException">name is null or empty.</exception>
/// <exception cref="SingletonException">A general error occured while trying to instantiate the SingletonController.</exception>
public SingletonController(string name, ISingletonEnforcer enforcer)
{
if (String.IsNullOrEmpty(name))
{
throw new ArgumentNullException("name", "name cannot be null or empty.");
}
if (enforcer == null)
{
throw new InvalidOperationException("the ISingletonInstanceEnforcer cannot be null");
}
try
{
_singleInstanceMutex = new Mutex(true, name, out _isFirstInstance);
string proxyObjectName = "SingletonProxy";
string proxyUri = "ipc://" + name + "/" + proxyObjectName;
// If no previous instance was found, create a server channel which will provide the proxy to the first created instance
if (_isFirstInstance)
{
// Create an IPC server channel to listen for SingletonProxy object requests
_ipcChannel = new IpcServerChannel(name);
// Register the channel and get it ready for use
ChannelServices.RegisterChannel(_ipcChannel, false);
// Register the service which gets the SingletonProxy object, so it can be accessible by IPC client channels
RemotingConfiguration.RegisterWellKnownServiceType(typeof(SingletonProxy), proxyObjectName, WellKnownObjectMode.Singleton);
// Create the first proxy object
_proxy = new SingletonProxy(enforcer);
// Publish the first proxy object so IPC clients requesting a proxy would receive a reference to it
RemotingServices.Marshal(_proxy, proxyObjectName);
}
else
{
// Create an IPC client channel to request the existing SingletonProxy object.
_ipcChannel = new IpcClientChannel();
// Register the channel and get it ready for use
ChannelServices.RegisterChannel(_ipcChannel, false);
// Retreive a reference to the proxy object which will be later used to send messages
_proxy = (SingletonProxy)Activator.GetObject(typeof(SingletonProxy), proxyUri);
}
}
catch (Exception ex)
{
throw new SingletonException("Failed to instantiate a new SingletonController object. See InnerException for more details.", ex);
}
}
