Question

我正在尝试将位于How to use signalr in android Service的代码从Java转换为c＃，并且已经取得了一些进展。我现在停留在最后一种方法上。 Java代码是：

private void startSignalR() {
    Platform.loadPlatformComponent(new AndroidPlatformComponent());
    mInstance.setmHubConnection();
    mInstance.setHubProxy();
    ClientTransport clientTransport = new ServerSentEventsTransport(mInstance.mHubConnection.getLogger());
    SignalRFuture<Void> signalRFuture = mInstance.mHubConnection.start(clientTransport);

    try {
        signalRFuture.get();
    } catch (InterruptedException | ExecutionException e) {
        Log.e("SimpleSignalR", e.toString());
        return;
    }

    mInstance.sendMessage(MainActivity.unm,"Hello All!");

    String CLIENT_METHOD_BROADAST_MESSAGE = "recievedMessage";
    mInstance.mHubProxy.on(CLIENT_METHOD_BROADAST_MESSAGE,
            new SubscriptionHandler2<String,LoginInfo>() {
                @Override
                public void run(final String msg,final LoginInfo loginInfo) {
                    final String finalMsg = loginInfo.FullName  + "  says " + loginInfo.Password;
                Intent intent = new Intent();
                intent.setAction(MY_ACTION);
                intent.putExtra("DATAPASSED", finalMsg);
                sendBroadcast(intent);
            }
        }
        , String.class,LoginInfo.class);
}

使用Java到C＃转换器，将其转换为：

    private void startSignalR()
    {
        Platform.loadPlatformComponent(new AndroidPlatformComponent());
        mInstance.setmHubConnection();
        mInstance.setHubProxy();
        ClientTransport clientTransport = new ServerSentEventsTransport(mInstance.mHubConnection.Logger);
        SignalRFuture<Void> signalRFuture = mInstance.mHubConnection.Start(clientTransport);

        try
        {
            signalRFuture.get();
        }
        catch (Exception e) when (e is InterruptedException || e is ExecutionException)
        {
            // Log.e("SimpleSignalR", e.ToString());
            return;
        }

        mInstance.sendMessage("", "Hello All!");

        string CLIENT_METHOD_BROADAST_MESSAGE = "recievedMessage";
        //String CLIENT_METHOD_BROADAST_MESSAGE = "messageReceived";
        mInstance.mHubProxy.on(CLIENT_METHOD_BROADAST_MESSAGE, new SubscriptionHandler2AnonymousInnerClass(this)
           , typeof(string), typeof(LoginInfo));
    }

    private class SubscriptionHandler2AnonymousInnerClass : SubscriptionHandler2<string, LoginInfo>
    {
        private readonly SignalRSrv outerInstance;

        public SubscriptionHandler2AnonymousInnerClass(SignalRSrv outerInstance)
        {
            this.outerInstance = outerInstance;
        }

        //JAVA TO C# CONVERTER WARNING: 'final' parameters are not available in .NET:
        //ORIGINAL LINE: @Override public void run(final String msg,final LoginInfo loginInfo)
        public override void run(string msg, LoginInfo loginInfo)
        {
            //JAVA TO C# CONVERTER WARNING: The original Java variable was marked 'final':
            //ORIGINAL LINE: final String finalMsg = loginInfo.FullName + "  says " + loginInfo.Password;
            string finalMsg = loginInfo.FullName + "  says " + loginInfo.Password;
            Intent intent = new Intent();
            intent.Action = MY_ACTION;
            intent.PutExtra("DATAPASSED", finalMsg);
            sendBroadcast(intent);
        }
    }

这当然会在Visual Studio 2017中产生一些错误。

首先，第Platform.loadPlatformComponent(new AndroidPlatformComponent());行生成了错误Platform is inaccessible due to its protection level。 Xamarin for Visual Studio 2017中的Platform确实受到保护，并且是System中的内部类，我无法更改它，因此我对如何进行操作感到困惑。同一行会生成错误The type or namespace name 'AndroidPlatformComponent' could not be found，这些错误很多且并非意外，我在Visual Studio 2017中找不到与AndroidPlatformComponent等效的错误，所以我无所适从。

接下来，在此行ClientTransport clientTransport = new ServerSentEventsTransport(mInstance.mHubConnection.Logger);上产生错误The type or namespace name 'ClientTransport' could not be found，我也找不到与此对应的错误，因此我不知所措。同样在这一行上，没有为集线器连接定义.Logger，显然在Java中它是.getLogger()，我也找不到与之等效的连接。

下一行SignalRFuture<Void> signalRFuture = mInstance.mHubConnection.Start(clientTransport);' generates the error 1The type or namespace name 'SignalRFuture<>' could not be found，这似乎是SignalR特有的，同样，我也找不到对应的内容。

下一个完全让我感到困惑，行private class SubscriptionHandler2AnonymousInnerClass : SubscriptionHandler2<string, LoginInfo>产生错误The type or namespace name 'SubscriptionHandler2<,>' could not be found。我在网上到处都看过，并在AnonymousInnerClass上阅读，但这没有帮助。

我希望这里的用户对SignalR以及c＃功能和java功能之间的区别更加熟悉。我一点也不熟悉Java，也不熟悉SignalR和前台服务。

Answer 1

事实证明，我正在转换的Java代码中的最后一个方法是连接一个事件，以将从集线器接收的消息传递给活动。在c＃/ Visual Studio（2017）中，这做的非常不同，这就是为什么我不了解/无法识别发生了什么的原因。因此，我在C＃中创建了一个处理程序，并为该消息执行了一条弹出消息。这本身可能会带来问题，但至少我知道发生了什么。这是我编写的用于从服务内部启动SignalR和WireUp处理程序的代码：

    private void startSignalR()
    {
        // Company, Department, and section are private variables
        // their values are pulled from the intent bundle 
        // in the OnBind method, that code is:
        //     Bundle bundlee = intent.GetBundleExtra("TheBundle");
        //     MyUser = bundlee.GetParcelable("MyUser") as User;
        // This information is put into the bundle when the user is logged in.
        // I then pass that information to the SignalR client 
        // when I set the hub connection and placed on the querystring to the hub.

        mInstance.setmHubConnection(username, firstname,lastname,company,department,section);
        mInstance.setHubProxy();

        try
        {
            // Connect the client to the hup
            mInstance.mHubConnection.Start();
            // Set the event handler
            mInstance.WireUp();

        }
        catch (System.Exception e) when (e is InterruptedException || e is ExecutionException)
        {
            ShowMessage("Error: + e.Message)
        }
    }

这是WireUp代码，这是客户端代码中的方法：

    public void WireUp()
    {
        // set the event handler
        mHubProxy.On("broadcastMessage", (string platform, string message) =>
        {
            if (OnMessageReceived != null)
                OnMessageReceived(this, string.Format("{0}: {1}", platform, message));
        });
    }

如我所料，当应用程序在后台运行时，不会显示弹出消息，因此我正在研究一种解决方法

将Java转换为C＃的问题

1 个答案: