/// <summary>
/// Create a Subscription to watch data changes
/// </summary>
/// <returns></returns>
public static Subscription CreateSubscription(this PlcDataMapper papper, ChangeDetectionStrategy changeDetectionStrategy = ChangeDetectionStrategy.Polling)
{
var sub = new Subscription(papper, changeDetectionStrategy);
papper.AddSubscription(sub);
return(sub);
}
/// <summary>
/// Subscribe to changes of variables
/// </summary>
/// <param name="mapper">Reference to plc data mapper</param>
/// <param name="callback">Callback method</param>
/// <param name="items">items to watch</param>
/// <param name="changeDetectionStrategy">setup the strategy to detect changes. <see cref="ChangeDetectionStrategy"/>. This setting depends on the access library.</param>
/// <returns></returns>
public static Subscription SubscribeDataChanges(this PlcDataMapper mapper,
OnChangeEventHandler callback,
int interval,
IEnumerable <PlcWatchReference> items,
ChangeDetectionStrategy changeDetectionStrategy = ChangeDetectionStrategy.Polling)
{
var subscription = new Subscription(mapper, changeDetectionStrategy, items, interval);
RunWatchTask(subscription, callback);
return(subscription);
}
/// <summary>
/// Create an instance of a subscription to detect plc data changes
/// </summary>
/// <param name="mapper">The reference to the plcDatamapper.</param>
/// <param name="vars">The variables we should watch.</param>
/// <param name="defaultInterval">setup the default interval, if none was given by the <see cref="PlcWatchReference"/></param>
public Subscription(PlcDataMapper mapper, ChangeDetectionStrategy changeDetectionStrategy = ChangeDetectionStrategy.Polling, IEnumerable <PlcWatchReference> vars = null, int defaultInterval = 1000)
{
_mapper = mapper ?? ExceptionThrowHelper.ThrowArgumentNullException <PlcDataMapper>(nameof(mapper));
_changeDetectionStrategy = changeDetectionStrategy;
_defaultInterval = defaultInterval;
_lock = new ReaderWriterLockSlim();
UpdateWatchCycle(vars);
if (changeDetectionStrategy == ChangeDetectionStrategy.Event)
{
_changeEvent = new AsyncAutoResetEvent <IEnumerable <DataPack> >();
}
if (vars != null)
{
AddItems(vars);
}
}
/// <summary>
/// Subscribe to changes of variables
/// </summary>
/// <param name="mapper">Reference to plc data mapper</param>
/// <param name="callback">Callback method</param>
/// <param name="items">items to watch</param>
/// <param name="changeDetectionStrategy">setup the strategy to detect changes. <see cref="ChangeDetectionStrategy"/>. This setting depends on the access library.</param>
/// <returns></returns>
public static Subscription SubscribeDataChanges(this PlcDataMapper mapper,
OnChangeEventHandler callback,
IEnumerable <PlcWatchReference> items,
ChangeDetectionStrategy changeDetectionStrategy = ChangeDetectionStrategy.Polling)
=> SubscribeDataChanges(mapper, callback, DefaultInterval, items as IEnumerable <PlcWatchReference>, changeDetectionStrategy);
