// 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();
}
}