/// <summary>
/// Gets a multicast instance or creates a new one.
/// </summary>
/// <param name="vmType">View model type helper.</param>
/// <param name="vmInstanceId">Optional view model instance identifier.</param>
/// <returns>View model instance.</returns>
private BaseVM GetMulticastInstance(TypeHelper vmType, string vmInstanceId)
{
string key = vmType.FullName;
MulticastVM vm = null;
lock (_keyBasedLock.GetOrAdd(key, _ => new object()))
{
if (!_memoryCache.TryGetValue(key, out HashSet <MulticastVM> vmCollections))
{
vm = CreateMulticastInstance(vmType, vmInstanceId, key);
vmCollections = new HashSet <MulticastVM> {
vm
};
_memoryCache.Set(key, vmCollections);
}
else
{
vm = vmCollections.FirstOrDefault(x => x.IsMember);
if (vm != null)
{
vm.AddRef();
}
else
{
vm = CreateMulticastInstance(vmType, vmInstanceId, key);
vmCollections.Add(vm);
}
}
}
return(vm);
}
/// <summary>
/// Removes multicast view model instance from the cache.
/// </summary>
/// <param name="vm">Multicast view model.</param>
/// <param name="key">Key to the cache collection, which is the view model's type name.</param>
private void RemoveMulticastInstance(MulticastVM vm, string key)
{
lock (_keyBasedLock.GetOrAdd(key, _ => new object()))
{
if (_memoryCache.TryGetValue(key, out HashSet <MulticastVM> vmCollections))
{
vmCollections.Remove(vm);
}
}
}
