// This KEPServerEX example shows how subscribe to changes of multiple items and display the value of the item with each change.
//
// Find all latest examples here: https://www.doc-that.com/files/onlinedocs/OPCLabs-ConnectivityStudio/Latest/examples.html .
// OPC client and subscriber examples in C# on GitHub: https://github.com/OPCLabs/Examples-ConnectivityStudio-CSharp .
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using System;
using System.Threading;
using OpcLabs.EasyOpc.DataAccess;
using OpcLabs.EasyOpc.DataAccess.OperationModel;

namespace DocExamples.Specialized
{
    partial class Kepware_KEPServerEX
    {
        public static void SubscribeMultipleItems()
        {
            // Instantiate the client object.
            using (var client = new EasyDAClient())
            {
                client.ItemChanged += client_SubscribeMultipleItems_ItemChanged;

                Console.WriteLine("Subscribing item changes...");
                client.SubscribeMultipleItems(
                    new[] {
                            new DAItemGroupArguments("", "Kepware.KEPServerEX.V6", "Simulation Examples.Functions.Random1", 1000, null), 
                            new DAItemGroupArguments("", "Kepware.KEPServerEX.V6", "Simulation Examples.Functions.Ramp1", 1000, null), 
                            new DAItemGroupArguments("", "Kepware.KEPServerEX.V6", "Simulation Examples.Functions.Sine1", 1000, null),  
                            new DAItemGroupArguments("", "Kepware.KEPServerEX.V6", "Simulation Examples.Functions.User1", 1000, null)
                        });

                Console.WriteLine("Processing item changed events for 1 minute...");
                Thread.Sleep(60 * 1000);

                Console.WriteLine("Unsubscribing item changes...");
            }

            Console.WriteLine("Finished.");
        }

        // Item changed event handler
        static void client_SubscribeMultipleItems_ItemChanged(object sender, EasyDAItemChangedEventArgs e)
        {
            if (e.Succeeded)
                Console.WriteLine($"{e.Arguments.ItemDescriptor.ItemId}: {e.Vtq}");
            else
                Console.WriteLine($"{e.Arguments.ItemDescriptor.ItemId} *** Failure: {e.ErrorMessageBrief}");
        }
    }
}