AdsClientExtensions.PollAdsState Method (IAdsConnection, IObservable.Unit.)

Gets an observable sequence of AdsStates via Polling.

Namespace:  TwinCAT.Ads.Reactive
Assembly:  TwinCAT.Ads.Reactive (in TwinCAT.Ads.Reactive.dll) Version: 4.3.0.0 (4.3.7.0)

Syntax

C#

public static IObservable<AdsState> PollAdsState(
    this IAdsConnection client,
    IObservable<Unit> trigger
)

VB

<ExtensionAttribute>
Public Shared Function PollAdsState ( 
    client As IAdsConnection,
    trigger As IObservable(Of Unit)
) As IObservable(Of AdsState)

Parameters

client

Type: TwinCAT.Ads.IAdsConnection
The client.

trigger

Type: System.IObservable.Unit.
The polling trigger

Return Value

Type: IObservable.AdsState.
IObservable<AdsState>.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type IAdsConnection. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).

Examples

The following sample shows how observe AdsState via polling with the reactive AdsClientExtensions

Observe changing ADS States with reactive extensions.

// To Test the observer, Start/Stop the local PLC

using (TcAdsClient client = new TcAdsClient())
{
    // Connect to target
    client.Connect(new AmsAddress(AmsNetId.Local, 851));

    // Create Symbol information
    var symbolLoader = SymbolLoaderFactory.Create(client, SymbolLoaderSettings.DefaultDynamic);

    // Reactive Change Handler
    var valueObserver = Observer.Create<IList<AdsState>>(not =>
    {
    AdsState oldValue = not[0];
    AdsState newValue = not[1];

    Console.WriteLine(string.Format("Changed ADSState from '{0}' --> '{1}!", oldValue, newValue));
    }
    );

    // Create a subscription for the AdsState change and buffering 2 Values (for oldValue --> newValue output).
    IDisposable subscription = client.PollAdsState(TimeSpan.FromMilliseconds(200)).Buffer(2, 1).Subscribe(valueObserver);

    Console.ReadKey(); // Wait for Key press
    subscription.Dispose(); // Dispose the Subscription
}

Reference

AdsClientExtensions Class

PollAdsState Overload

TwinCAT.Ads.Reactive Namespace

AdsClientExtensions.WhenAdsStateChanges(TcAdsClient)