终于找到一个MIT License的Opc Ua客户端

源代码在这个地方，自己去下载，如果需要

https://github.com/convertersystems/opc-ua-client

老规矩先装包：

dotnet add package Workstation.UaClient --version 3.2.0

实际上官方给到的示例已经足够好用了，我这里记录一下我的实验过程

代码是这些：

using Workstation.ServiceModel.Ua.Channels;
using Workstation.ServiceModel.Ua;

Console.WriteLine("Hello, World!");
Thread.Sleep(1000);
// describe this client application.
var clientDescription = new ApplicationDescription {
    ApplicationName = "Workstation.UaClient.FeatureTests",
    ApplicationUri = $"urn:{System.Net.Dns.GetHostName()}:Workstation.UaClient.FeatureTests",
    ApplicationType = ApplicationType.Client
};

// create a 'ClientSessionChannel', a client-side channel that opens a 'session' with the server.
var channel = new ClientSessionChannel(
    clientDescription,
    null, // no x509 certificates
    new AnonymousIdentity(), // no user identity
    "opc.tcp://localhost:4840", // the public endpoint of a server at opcua.rocks.
    SecurityPolicyUris.None); // no encryption
try
{
    // try opening a session and reading a few nodes.
    await channel.OpenAsync();

    Console.WriteLine($"Opened session with endpoint '{channel.RemoteEndpoint.EndpointUrl}'.");
    Console.WriteLine($"SecurityPolicy: '{channel.RemoteEndpoint.SecurityPolicyUri}'.");
    Console.WriteLine($"SecurityMode: '{channel.RemoteEndpoint.SecurityMode}'.");
    Console.WriteLine($"UserIdentityToken: '{channel.UserIdentity}'.");

    // build a ReadRequest. See 'OPC UA Spec Part 4' paragraph 5.10.2
    var readRequest = new ReadRequest {
        // set the NodesToRead to an array of ReadValueIds.
        NodesToRead = new[] {
                    // construct a ReadValueId from a NodeId and AttributeId.
                    new ReadValueId {
                        // you can parse the nodeId from a string.
                        // e.g. NodeId.Parse("ns=2;s=Demo.Static.Scalar.Double")
                        NodeId = NodeId.Parse(VariableIds.Server_ServerStatus),
                        // variable class nodes have a Value attribute.
                        AttributeId = AttributeIds.Value
                    }
                }
    };
    // send the ReadRequest to the server.
    var readResult = await channel.ReadAsync(readRequest);

    // DataValue is a class containing value, timestamps and status code.
    // the 'Results' array returns DataValues, one for every ReadValueId.
    var serverStatus = readResult.Results[0].GetValueOrDefault<ServerStatusDataType>();

    Console.WriteLine("\nServer status:");
    Console.WriteLine("  ProductName: {0}", serverStatus.BuildInfo.ProductName);
    Console.WriteLine("  SoftwareVersion: {0}", serverStatus.BuildInfo.SoftwareVersion);
    Console.WriteLine("  ManufacturerName: {0}", serverStatus.BuildInfo.ManufacturerName);
    Console.WriteLine("  State: {0}", serverStatus.State);
    Console.WriteLine("  CurrentTime: {0}", serverStatus.CurrentTime);

    Console.WriteLine($"\nClosing session '{channel.SessionId}'.");
    await channel.CloseAsync();
}
catch (Exception ex)
{
    await channel.AbortAsync();
    Console.WriteLine(ex.Message);
}
Console.ReadLine();

 步骤是这样的：

1. 先启动一个Opc Ua 服务器

这边用的是Opc.UaFx.Advanced这个包做的简单服务器，千万不要学我，这玩意不能直接商用的，买授权折人民币6万左右。

2. 启动上面那段代码的客户端程序

 

呐，这里把上面那个Opc Ua服务器的信息打印出来了，说明可以用的，这个实验中客户端程序是MIT Licence的，放心商用，服务器端是要购买授权的。

由于我个人版权意识淡漠，用基金会的程序集做项目差点酿成大祸，大家千万不要学我，一定要白嫖MIT License的。

有Opc Ua，ModbusTcp，串口问题可以评论或者联系我。