(.NET Core C#) Async TaskCompleted Callback

Demonstrates the use of the TaskCompleted callback for async method calls (i.e. for Chilkat asynchronous methods where the method name ends with "Async").

NOTE: This is very important: The TaskCompleted callback runs in the background thread. (All callbacks from an async task, such as AbortCheck, PercentDone, ProgressInfo, etc. are in the background thread.) An application that uses TaskCompleted must be very careful. For example, user interface elements (such as labels, text boxes, etc.) may not be directly accessible from a background thread, and could crash the application if directly accessed. Also, attempting to debug code running in a background thread from an IDE is likely to crash the IDE.

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// TaskCompleted callback method.
public void handleTaskCompleted(int taskId)
    {
    // Application code goes here.
    }

private void ChilkatExample()
    {
    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    Chilkat.Http http = new Chilkat.Http();

    Chilkat.Http.TaskCompleted taskCompleted = new Chilkat.Http.TaskCompleted(handleTaskCompleted);
    http.setTaskCompletedCb(taskCompleted);

    bool success;

    Chilkat.Xml soapXml = new Chilkat.Xml();

    soapXml.Tag = "soap12:Envelope";
    success = soapXml.AddAttribute("xmlns:xsi","http://www.w3.org/2001/XMLSchema-instance");
    success = soapXml.AddAttribute("xmlns:xsd","http://www.w3.org/2001/XMLSchema");
    success = soapXml.AddAttribute("xmlns:soap12","http://www.w3.org/2003/05/soap-envelope");

    soapXml.NewChild2("soap12:Body","");
    success = soapXml.GetChild2(0);
    soapXml.NewChild2("GetCityWeatherByZIP","");
    success = soapXml.GetChild2(0);
    success = soapXml.AddAttribute("xmlns","http://ws.cdyne.com/WeatherWS/");
    soapXml.NewChild2("ZIP","60187");
    soapXml.GetRoot2();

    Debug.WriteLine(soapXml.GetXml());

    Chilkat.HttpRequest req = new Chilkat.HttpRequest();
    req.HttpVerb = "POST";
    req.SendCharset = false;
    req.AddHeader("Content-Type","application/soap+xml; charset=utf-8");
    req.AddHeader("SOAPAction","http://ws.cdyne.com/WeatherWS/GetCityWeatherByZIP");
    req.Path = "/WeatherWS/Weather.asmx";
    success = req.LoadBodyFromString(soapXml.GetXml(),"utf-8");

    http.FollowRedirects = true;

    // The name of "SynchronousRequestAsync" method is somewhat confusing. This is explained here:

    // Any Chilkat method that utilizes callbacks will have an Async version of the method.
    // The name of the Async method is the method name appended with "Async".  For example,
    // if the method is named "Abc", then the async method is "AbcAsync".
    // The Async method always returns a Chilkat Task object.

    // In the years prior to Chilkat introducing the Async functionality, this particular method's
    // name was already "SynchronousRequest".  The async versionof the method is therefore
    // "SynchronousRequestAsync" (just like "Abc" --> "AbcAsync").  Yes, it's confusing and we apologize.. 
    Chilkat.Task task = http.SynchronousRequestAsync("wsf.cdyne.com",80,false,req);
    if (http.LastMethodSuccess != true) {
        Debug.WriteLine(http.LastErrorText);
        return;
    }

    // Schedule the task for running on the thread pool.  This changes the task's state
    // from Inert to Live.
    success = task.Run();
    if (success != true) {
        Debug.WriteLine(task.LastErrorText);

        return;
    }

    // The application is now free to do anything else
    // while the HTTP request is in progress.  When the task
    // is completed, the TaskCompleted method is called.

    // -------------------------------------------------------------------------------
    // The following is a general note that applies to all programming languages:
    // -------------------------------------------------------------------------------

    // NOTE: This is very important:  The TaskCompleted callback runs in the background thread.  
    // (All callbacks from an async task, such as AbortCheck, PercentDone, ProgressInfo, etc. are in the background thread.) 
    // An application that uses TaskCompleted must be very careful.  
    // For example, user interface elements (such as labels, text boxes, etc.) may not be directly
    // accessible from a background thread, and could crash the application if directly accessed.  Also, attempting to debug
    // code running in a background thread from an IDE, especially an older IDE (such as VB6) is likely to crash the IDE.

    }