使用 opc ua .net 库在 Unity3d 中创建一个非常简单的 OPC 客户端

Question

我在尝试使用 Unity3D 在 .Net 中实现一个简单的 OPC 客户端时遇到这些错误。这些错误在 Visual Studio 中：

Severity    Code    Description Project File    Line    Suppression State
Error   CS0012  The type 'X509CertificateValidator' is defined in an assembly that is not referenced. You must add a reference to assembly 'System.ServiceModel.Primitives, Version=4.5.0.3, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'. Test    C:\Users\hidethepain\Documents\opc\Assets\main.cs   27  

Severity    Code    Description Project File    Line    Suppression State
Error   CS0012  The type 'Enum' is defined in an assembly that is not referenced. You must add a reference to assembly 'netstandard, Version=2.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51'.    Test, Test.Player   C:\Users\hidethepain\Documents\opc\Assets\main.cs   18  Active

Severity    Code    Description Project File    Line    Suppression State
Error   CS0012  The type 'Task<>' is defined in an assembly that is not referenced. You must add a reference to assembly 'netstandard, Version=2.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51'.  Test, Test.Player   C:\Users\hidethepain\Documents\opc\Assets\main.cs   31  Active

还有其他 49 个类似的错误。

Unity3D 向我显示此错误：

Assets/main.cs(67,40): error CS0012: The type `System.Object' is defined in an assembly that is not referenced. Consider adding a reference to assembly `netstandard, Version=2.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51'

Unity3D 使用脚本运行时版本 .Net 3.5 我将其更改为 .NET 4.6 以便能够使用 OPC Library。

这是我的代码：

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using System;
using Opc.Ua; 
using Opc.Ua.Client;
using Opc.Ua.Configuration;

public class main : MonoBehaviour
{

    private async void Start()
    {
        Console.WriteLine("Step 1 - Create a config.");
        var config = new ApplicationConfiguration()
        {
            ApplicationName = "test-opc",
            ApplicationType = ApplicationType.Client,
            SecurityConfiguration = new SecurityConfiguration { ApplicationCertificate = new CertificateIdentifier() },
            TransportConfigurations = new TransportConfigurationCollection(),
            TransportQuotas = new TransportQuotas { OperationTimeout = 15000 },
            ClientConfiguration = new ClientConfiguration { DefaultSessionTimeout = 60000 }
        };
        await config.Validate(ApplicationType.Client);
        if (config.SecurityConfiguration.AutoAcceptUntrustedCertificates)
        {
            config.CertificateValidator.CertificateValidation += (s, e) => { e.Accept = (e.Error.StatusCode == StatusCodes.BadCertificateUntrusted); };
        }

        Console.WriteLine("Step 2 - Create a session with your server.");
        using (var session = await Session.Create(config, new ConfiguredEndpoint(null, new EndpointDescription("opc.tcp://localhost:4841")), true, "", 60000, null, null))
        {
            Console.WriteLine("Step 3 - Browse the server namespace.");
            ReferenceDescriptionCollection refs;
            byte[] cp;
            session.Browse(null, null, ObjectIds.ObjectsFolder, 0u, BrowseDirection.Forward, ReferenceTypeIds.HierarchicalReferences, true, (uint)NodeClass.Variable | (uint)NodeClass.Object | (uint)NodeClass.Method, out cp, out refs);
            Console.WriteLine("DisplayName: BrowseName, NodeClass");
            foreach (var rd in refs)
            {
                Console.WriteLine(rd.DisplayName + ": " + rd.BrowseName + ", " + rd.NodeClass);
                ReferenceDescriptionCollection nextRefs;
                byte[] nextCp;
                session.Browse(null, null, ExpandedNodeId.ToNodeId(rd.NodeId, session.NamespaceUris), 0u, BrowseDirection.Forward, ReferenceTypeIds.HierarchicalReferences, true, (uint)NodeClass.Variable | (uint)NodeClass.Object | (uint)NodeClass.Method, out nextCp, out nextRefs);
                foreach (var nextRd in nextRefs)
                {
                    Console.WriteLine("+ " + nextRd.DisplayName + ": " + nextRd.BrowseName + ", " + nextRd.NodeClass);
                }
            }

            Console.WriteLine("Step 4 - Create a subscription. Set a faster publishing interval if you wish.");
            var subscription = new Subscription(session.DefaultSubscription) { PublishingInterval = 1000 };

            Console.WriteLine("Step 5 - Add a list of items you wish to monitor to the subscription.");
            var list = new List<MonitoredItem> {
                new MonitoredItem(subscription.DefaultItem) { DisplayName = "aaatime", StartNodeId = "i=10004" } };
            list.ForEach(i => i.Notification += OnNotification);
            subscription.AddItems(list);

            Console.WriteLine("Step 6 - Add the subscription to the session.");
            session.AddSubscription(subscription);
            subscription.Create();

            Console.WriteLine("Finished client initialization");
        }
    }

    private static void OnNotification(MonitoredItem item, MonitoredItemNotificationEventArgs e)
    {
        foreach (var value in item.DequeueValues())
        {
            Console.WriteLine("{0}: {1}, {2}, {3}", item.DisplayName, value.Value, value.SourceTimestamp, value.StatusCode);
        }
    }
}

代码从.Net Core example 移植到 Unity3d。 我该如何解决这些错误？

Answer 1

GitHub OPC Unified Architecture .NET Standard 的文档说最低要求是 .NET Standard 2.0。
根据 Unity 论坛What .NET stack for UWP/HoloLens? 的说法，只要在 Player Settings 中选择 .NET 作为 Scripting Backend，开发人员就只能使用 .NET Standard 1.4 版。

我没有测试这个特定的库，但我认为当你切换到 IL2CPP 时它应该可以工作，因为它支持 2.0。

从 2018.2 版本开始，Unity 将 .NET 标记为已弃用，因此我认为他们将来不会大力改变这种情况，而是会专注于 IL2CPP。
真可惜，我喜欢 .NET 的短构建周期