Question

我在使用关联类型作为协议时遇到问题：

private static TelemetryClient telemetryClient = new TelemetryClient();

private static System.Timers.Timer aTimer;

    static void Main(string[] args)
    {

        // Register Unhandled Exception Handler
        AppDomain.CurrentDomain.UnhandledException += CurrentDomain_UnhandledException;
        // Set the Instrumentation Key to track the WebJob Exception
        TelemetryConfiguration.Active.InstrumentationKey = SecureConfigReader.GetSetting("ApplicationInsightsKey");


        Configure();

        if (args.Length > 0)
        {
            // Create a timer with a ten second interval.
            aTimer = new System.Timers.Timer(10000);
            // Hook up the Elapsed event for the timer.
            aTimer.Elapsed += new ElapsedEventHandler(OnTimedEvent);
            double Scheduled_Interval = Convert.ToDouble(args[0]);
            // Set the Interval to 300 seconds.
            aTimer.Interval = TimeSpan.FromSeconds(Scheduled_Interval).TotalMilliseconds;
            aTimer.Enabled = true;

            Console.WriteLine("Press the Enter key to exit the program.");
            Console.ReadLine();
        }
    }


    private static void OnTimedEvent(object source, ElapsedEventArgs e)
    {
        Console.WriteLine("The Elapsed event was raised at {0}", e.SignalTime);
        RunTests();

    }
    private static void CurrentDomain_UnhandledException(object sender, UnhandledExceptionEventArgs e)
    {
        ExceptionTelemetry excTelemetry = new ExceptionTelemetry((Exception)e.ExceptionObject);
        excTelemetry.SeverityLevel = SeverityLevel.Critical;
        excTelemetry.HandledAt = ExceptionHandledAt.Unhandled;
        telemetryClient.InstrumentationKey = SecureConfigReader.GetSetting("ApplicationInsightsKey");
         telemetryClient.TrackException(excTelemetry);
        //make sure all telemetry is sent before closing the app
        telemetryClient.Flush();
    }

    /*
     * 1. Find all tests
     * 2. Run all tests, collecting all results
     * 3. Process alerts if any
     * 4. Save results
     */
    private static void RunTests()
    {

        List<SyntheticTransactionTableEntity> results = new List<SyntheticTransactionTableEntity>();
        List<ISyntheticTransaction> tests = new List<ISyntheticTransaction>();
     }

当我尝试实现搜索结果协议时，我遇到编译问题：

“类型SearchArticles不符合协议SearchResultsProtocol”

NotificationCenter.default.addObserver(self, selector: #selector(YourClassName.fetchedUser), name: notificationName, object: nil)

据我了解，这是因为SearchArticles类中的T不是来自具体类型（该示例中的struct），而是来自协议类型。

有没有办法解决这个问题？

提前致谢！

Answer 1

associatedtype并不是一个占位符（协议），它应该是一个具体的类型。通过在类声明中添加泛型，您可以获得与此相同的结果....

class SearchArticles<V: ArticleProtocol>: SearchResultsProtocol {
    typealias T = V
}

然后，当您在应用周围使用SearchArticles时，您可以声明let foo = SearchArticles<FirstArticle>或let foo = SearchArticles<SecondArticle>

协议类型的Swift associatedType - 怎么做？

1 个答案: