// This example shows how to handle the read event on a folder, providing a way to implement reading of multiple data
// variables using a single handler.
// You can use any OPC UA client, including our Connectivity Explorer and OpcCmd utility, to connect to the server.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
// OPC client, server and subscriber examples in C# on GitHub: https://github.com/OPCLabs/Examples-OPCStudio-CSharp .
// Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own
// a commercial license in order to use Online Forums, and we reply to every post.
using System;
using OpcLabs.BaseLib.NodeSpace;
using OpcLabs.EasyOpc.UA;
using OpcLabs.EasyOpc.UA.NodeSpace;
using OpcLabs.EasyOpc.UA.OperationModel;
namespace UAServerDocExamples._UAServerNode
{
class Read
{
public static void Main1()
{
// Instantiate the server object.
// By default, the server will run on endpoint URL "opc.tcp://localhost:48040/".
var server = new EasyUAServer();
// Create a folder node.
UAFolder myFolder = UAFolder.CreateIn(server.Objects, "MyFolder");
// Create data variables in the folder. Distinguish them by their state.
myFolder.Add(new UADataVariable("MyDataVariable1").ValueType<int>().SetState(1));
myFolder.Add(new UADataVariable("MyDataVariable2").ValueType<int>().SetState(2));
myFolder.Add(new UADataVariable("MyDataVariable3").ValueType<int>().SetState(3));
myFolder.Add(new UADataVariable("MyDataVariable4").ValueType<int>().SetState(4));
myFolder.Add(new UADataVariable("MyDataVariable5").ValueType<int>().SetState(5));
// Handle the read event for the folder.
myFolder.Read += MyFolderOnRead;
// Start the server.
Console.WriteLine("The server is starting...");
server.Start();
Console.WriteLine("The server is started.");
Console.WriteLine();
// Let the user decide when to stop.
Console.WriteLine("Press Enter to stop the server...");
Console.ReadLine();
// Stop the server.
Console.WriteLine("The server is stopping...");
server.Stop();
Console.WriteLine("The server is stopped.");
}
/// <summary>
/// Event handler for the read event on the folder.
/// </summary>
/// <param name="sender">The folder object that sends the event.</param>
/// <param name="e">Data for the variable read event.</param>
static private void MyFolderOnRead(object sender, UADataVariableReadEventArgs e)
{
// Obtain the state associated with the data variable that is being read.
// Use it as the offset for the random value, so that each data variable generates values in a unique range.
int offset = (int)e.DataVariable.State*100;
// Generate a random value, indicate that the read has been handled, and return the generated value.
e.HandleAndReturn(Random.Next(offset, offset + 100));
}
static private readonly Random Random = new Random();
}
}
' This example shows how to handle the read event on a folder, providing a way to implement reading of multiple data
' variables using a single handler.
' You can use any OPC UA client, including our Connectivity Explorer and OpcCmd utility, to connect to the server.
'
' Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
' OPC client and subscriber examples in VB.NET on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-VBNET .
' Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own
' a commercial license in order to use Online Forums, and we reply to every post.
Imports System
Imports OpcLabs.BaseLib.NodeSpace
Imports OpcLabs.EasyOpc.UA
Imports OpcLabs.EasyOpc.UA.NodeSpace
Imports OpcLabs.EasyOpc.UA.OperationModel
Namespace _UAServerNode
Partial Friend Class Read
Shared Sub Main1()
' Instantiate the server object.
' By default, the server will run on endpoint URL "opc.tcp://localhost:48040/".
Dim server = New EasyUAServer()
' Create a folder node.
Dim myFolder As UAFolder = UAFolder.CreateIn(server.Objects, "MyFolder")
' Create data variables in the folder. Distinguish them by their state.
myFolder.Add(New UADataVariable("MyDataVariable1").ValueType(Of Integer)().SetState(1))
myFolder.Add(New UADataVariable("MyDataVariable2").ValueType(Of Integer)().SetState(2))
myFolder.Add(New UADataVariable("MyDataVariable3").ValueType(Of Integer)().SetState(3))
myFolder.Add(New UADataVariable("MyDataVariable4").ValueType(Of Integer)().SetState(4))
myFolder.Add(New UADataVariable("MyDataVariable5").ValueType(Of Integer)().SetState(5))
' Handle the read event for the folder.
AddHandler myFolder.Read, AddressOf MyFolderOnRead
' Start the server.
Console.WriteLine("The server is starting...")
server.Start()
Console.WriteLine("The server is started.")
Console.WriteLine()
' Let the user decide when to stop.
Console.WriteLine("Press Enter to stop the server...")
Console.ReadLine()
' Stop the server.
Console.WriteLine("The server is stopping...")
server.Stop()
Console.WriteLine("The server is stopped.")
End Sub
''' <summary>
''' Event handler for the read event on the folder.
''' </summary>
''' <param name="sender">The data variable object that sends the event.</param>
''' <param name="e">Data for the variable read event.</param>
Private Shared Sub MyFolderOnRead(ByVal sender As Object, ByVal e As UADataVariableReadEventArgs)
' Obtain the state associated with the data variable that is being read.
' Use it as the offset for the random value, so that each data variable generates values in a unique range.
Dim offset As Integer = CInt(e.DataVariable.State * 100)
' Generate a random value, indicate that the read has been handled, and return the generated value.
e.HandleAndReturn(Random.Next(offset, offset + 100))
End Sub
Private Shared ReadOnly Random As Random = New Random()
End Class
End Namespace
