// This example shows how to read items while subscribed.
using System;
using System.Diagnostics;
using System.Threading;
using OpcLabs.EasyOpc.DataAccess;
using OpcLabs.EasyOpc.DataAccess.OperationModel;
namespace DocExamples.DataAccess._EasyDAClient
{
partial class SubscribeMultipleItems
{
public static void WithRead()
{
// Instantiate the client object.
using (var client = new EasyDAClient())
{
client.ItemChanged += client_Read_ItemChanged;
Console.WriteLine("Subscribing item changes...");
client.SubscribeMultipleItems(
new[] {
new DAItemGroupArguments("", "OPCLabs.KitServer.2", "Simulation.Random", 1000, null),
new DAItemGroupArguments("", "OPCLabs.KitServer.2", "Trends.Sine (1 min)", 1000, null),
});
Console.WriteLine("Waiting for 10 seconds...");
Thread.Sleep(10 * 1000);
Console.WriteLine("Reading items...");
DAVtqResult[] vtqResults = client.ReadMultipleItems("OPCLabs.KitServer.2",
new DAItemDescriptor[]
{
"Trends.Ramp (1 min)", "Trends.Sine (1 min)"
});
for (int i = 0; i < vtqResults.Length; i++)
{
Debug.Assert(vtqResults[i] != null);
if (vtqResults[i].Succeeded)
Console.WriteLine("vtqResults[{0}].Vtq: {1}", i, vtqResults[i].Vtq);
else
Console.WriteLine("vtqResults[{0}] *** Failure: {1}", i, vtqResults[i].ErrorMessageBrief);
}
Console.WriteLine("Waiting for 10 seconds...");
Thread.Sleep(10 * 1000);
Console.WriteLine("Unsubscribing item changes...");
}
Console.WriteLine("Finished.");
}
// Item changed event handler
static void client_Read_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}");
}
}
}
# This example shows how to read items while subscribed.
# The QuickOPC package is needed. Install it using "pip install opclabs_quickopc".
import opclabs_quickopc
import time
# Import .NET namespaces.
from OpcLabs.EasyOpc import *
from OpcLabs.EasyOpc.DataAccess import *
from OpcLabs.EasyOpc.DataAccess.OperationModel import *
# Item changed event handler.
def itemChanged(sender, e):
if e.Succeeded:
print('< ', e.Arguments.ItemDescriptor.ItemId, ': ', e.Vtq, sep='')
else:
print('< ', e.Arguments.ItemDescriptor.ItemId, ' *** Failure: ', e.ErrorMessageBrief, sep='')
# Instantiate the client object.
client = EasyDAClient()
client.ItemChanged += itemChanged
print('Subscribing item changes...')
client.SubscribeMultipleItems([
EasyDAItemSubscriptionArguments('', 'OPCLabs.KitServer.2', 'Simulation.Random', 1000, None),
EasyDAItemSubscriptionArguments('', 'OPCLabs.KitServer.2', 'Trends.Sine (1 min)', 1000, None),
])
print('Processing item change notifications for 10 seconds...')
time.sleep(10)
print('Reading items...')
vtqResultArray = client.ReadMultipleItems([
DAReadItemArguments(ServerDescriptor('OPCLabs.KitServer.2'), DAItemDescriptor('Trends.Ramp (1 min)')),
DAReadItemArguments(ServerDescriptor('OPCLabs.KitServer.2'), DAItemDescriptor('Trends.Sine (1 min)')),
])
for i, vtqResult in enumerate(vtqResultArray):
assert vtqResult is not None
if vtqResult.Succeeded:
print('vtqResultArray[', i, '].Vtq: ', vtqResult.Vtq, sep='')
else:
print('vtqResultArray[', i, '] *** Failure: ', vtqResult.ErrorMessageBrief, sep='')
print('Processing item change notifications for 10 seconds...')
time.sleep(10)
print('Unsubscribing all items...')
client.UnsubscribeAllItems()
client.ItemChanged -= itemChanged
print('Finished.')
