A Task

Introduction

At this time, we know that, to get an application working in a computer, you create one or more threads. Each thread is in charge of performing a particular operation. Such an operation is called a task.

Synchronous Operations

Imagine you have one line of trains on a single set of rails between two locations. In one location, you assemble and produce some objects, such as vehicles, that you must ship to the other location where they are sold at a car dealership:

Since you have only one line of trains, only one train can travel at a time to deliver the products from the starting point to the other. Only one train at a time can start from the manufacturer. If many trains must travel from the manufacturer, only one must start. The next train would start only after the previous one has left. In this type of scenario, one operation (a train leaving the station) must complete before the next (similar) operation starts (before the next train leaves the station). Your business operating with one line of trains would be called a single-threaded application. This is referred to as a synchronous operation.

Introduction to Asynchronous Operations

With only one line of trains, you can make only one delivery. Each train must wait for the one ahead to leave. Because your employees must keep track of all the movements of all trains and avoid accidents, one of the things they must do is to always block many of the operations in order to conduct one particular operation. In fact, if something bad, such as an accident, happens to the running train, everything must stop until the problem is addressed or fixed. This can slow your business and make merchandise delivery take too much time.

Imagine your business starts growing. One, and probably the best, thing you can do to deliver more products (and consequently work faster) is to have more than one line of trains. That way, different trains carrying merchandise can leave the manufacturer at the same time. In fact, you can have as many trains leaving the manufacturer as train lines are available:

In fact also, different trains can leave at different times:

This means that the departing and/or the activities of one train don’t depend on another train. In fact, even if one train is having problems, such as an accident, on one line, the other trains would still operate. You can also distribute work. For example, you can:

• Load all trains with the same types and the same number of vehicles
• Load a mix of small vehicles and trucks in all trains
• Use a small train with fewer wagons to carry small cars, and use bigger trains to carry big vehicles such as SUVs
• Let some trains travel at certain times of the day and let some other special trains run at other times of the day or night

Introduction to Task Procedures

An Action Task

Some operations on a computer use a lot of resources and some operations take a long time to complete. One of the consequences is that one operation could block resources or processing time that other operations may need. One of the ways you can make operations run faster in your project is to run many operations at the same time. This concept certainly also applies when various users, using various browsers, different browsers, or various tabs at the same time, try to access the same webpage, the same video of a website (actually the webserver), the same database, the same file, etc. To eliminate or reduce the likelihood of operations interfering with each other, we saw that you create threads and run each thread on its own area of of work. This means that the threads, or various operations, are running asynchronously. To make this possible, the .NET Framework provides the concepts of tasks.

A task is an operation that runs in a manner that it would not interfere with other operations (that is, other tasks) on the same computer. This means that a task is an operation that runs asynchronously. Compared to functions (or methods of a class), the .NET Framework provides two categories of tasks: those that don't produce a result (also called procedures) and those that return a value or an object (also called functions).

To support tasks, that is, to allow you to create one or more tasks, the .NET Framework provides a class named Task. This class is defined in the System.Threading.Tasks namespace.

The Task class uses many constructors for different goals. The simplest constructor uses the following syntax:

public Task(Action action);

This version of the Task constructor takes a void method as argument. You can pass the name of the method as argument. Here is an example:

using System.Web.Mvc;
using System.Threading;
using System.Threading.Tasks;

namespace Exercises.Controllers
{
    public delegate double Operation(double a, double b);

    public class HomeController : Controller
    {
        public ActionResult Index()
        {
            Task wisdom = new Task(TurkishProverb);

            return View();
        }

        private void TurkishProverb()
        {
            Response.Write("<p>A tree won't fall with a single blow</p>");
        }
    }
}

You can also define the method directly where it is needed. Here is an example:

using System.Web.Mvc;
using System.Threading;
using System.Threading.Tasks;

namespace Exercises.Controllers
{
    public class HomeController : Controller
    {
        public ActionResult Index()
        {
            Task wisdom = new Task(() =>
	    {
    	        Response.Write("<p>A tree won't fall with a single blow</p>");
    	    });

            return View();
        }
    }
}

Starting a Task

After creating a task, you can launch its operation. To support this, the Task class is equipped with a method named Start. It is overloaded with two versions. The simplest version uses the following syntax:

public void Start();

Simply call this method to perform the task. Here is an example:

using System.Web.Mvc;
using System.Threading;
using System.Threading.Tasks;

namespace Exercises.Controllers
{
    public class HomeController : Controller
    {
        public ActionResult Index()
        {
            Task wisdom = new Task(TurkishProverb);

            wisdom.Start();

            return View();
        }

        private void TurkishProverb()
        {
            Response.Write("<p>A tree won't fall with a single blow</p>");
        }
    }
}

Running a Task

In the above code, we first defined a task before starting it. As an alternative, the Task class provides an overloaded method named Run. It is available in various versions for different goals. Consider the following code:

using System.Web.Mvc;
using System.Threading.Tasks;

namespace Exercises.Controllers
{
    public class StudiesController : Controller
    {
        public ActionResult Index()
        {
             Task warning = new Task(SocialScience);

            warning.Start();

            return View();
        }

        public  void SocialScience()
        {
            Response.Write("<p>When you commit a suicide, the worse thing that can happen to you is that you don't die.</p>");
        }
    }
}

To call the Task.Run() method, you don't have to first create a method for the task. You can call the Task.Run() method as a combination of defining the method and starting it. You can first define a local Action expression, then pass its name as argument. Here is an example:

using System.Web.Mvc;
using System.Threading.Tasks;

namespace Exercises.Controllers
{
    public class StudiesController : Controller
    {
        public ActionResult Index()
        {
            Action sayit = () =>
            {
                Response.Write("<p>When you commit a suicide, the worse thing that can happen to you is that you don't die.</p>");
            };

            Task warning = Task.Run(sayit);

            return View();
        }
    }
}

Alternatively, you can create a lambda expression in the parentheses of the method. Here is an example:

using System.Web.Mvc;
using System.Threading.Tasks;

namespace Exercises.Controllers
{
    public class StudiesController : Controller
    {
        public ActionResult Index()
        {
            Task warning = Task.Run(() =>
            {
                Response.Write("<p>When you commit a suicide, the worse thing that can happen to you is that you don't die.</p>");
            });

            return View();
        }
}

A Procedure Task as a Type

A Task object can be used as a type. This means that you can create a method that takes a task as argument. In the same way, a method can return a task. Here is an example:

using System.Web.Mvc;
using System.Threading.Tasks;

namespace Exercises.Controllers
{
    public class StudiesController : Controller
    {
        public ActionResult Index()
        {
            Task something = Visit();

            something.Start();

            return View();
        }

        public Task Visit()
        {
            Task wisdom = new Task(() =>
            {
                Response.Write("<p>Thank you for your visit</p>");
            });

            return wisdom;
        }
    }
}

Introduction to Functional Tasks

A Functional Task

As seen with functions in previous lessons, some operations must produce a value. That's the case for methods that return a value or an object. To support tasks that produce a value, the .NET Framework provides a generic Task<> class. In fact, this class inherits from the non-generic Task class:

public class Task<TResult> : Task

Practical Learning: Introducing Functional Tasks

1. Start Microsoft Visual Studio
2. On the main menu, click File -> New -> Project...
3. In the New Project dialog box, click ASP.NET Application (.NET Framewoork) and change the project Name to RedOakHighSchool1
4. Click OK
5. In the New ASP.NET Application dialog box, click the MVC icon and click OK
6. In the Solution Explorer, right-click Controllers -> Add -> New Scaffolded Item...
7. In the Add Scaffold dialog box, click MVC 5 Controller - Empty and press Enter
8. Type Academics as the name of the controller to get AcademicsController
9. Click Add
10. Create a method as follows:

    using System.Web.Mvc;
    
    namespace RedOakHighSchool.Controllers
    {
        public class AcademicsController : Controller
        {
            // GET: Academics
            public ActionResult Index()
            {
                return View();
            }
    
            // GET: Academics/StartGradeReport
            public ActionResult GradeReportStartUp()
            {
                return View();
            }
    
            // GET: Academics/GradeReportPreparation
            public ActionResult GradeReportPreparation()
            {
                return View();
            }
        }
    }

11. In the Solution Explorer, below Views, right-click Academics -> Add -> New Scaffolded Item...
12. In the Add Scaffold dialog box, click MVC 5 View
13. Click Add
14. Type GradeReportPreparation as the name of the view
15. Click Add
16. In the Solution Explorer, below Views, right-click Academics -> Add -> View...
17. Type GradeReportStartUp as the name of the view
18. Press Enter
19. Create a form as follows:

    @{
        ViewBag.Title = "Grade Report Start-Up";
    }
    
    <h1>Red Oak High School</h1>
    <h2>Grade Report Start-Up</h2>
    
    @using (Html.BeginForm("GradeReportPreparation", "Academics", FormMethod.Post))
    {
        <table border="6">
            <tr>
                <td><b>Course Name</b></td>
                <td style="width: 140px; font-weight: 600; text-align: center">1st Semester</td>
                <td style="width: 140px; font-weight: 600; text-align: center">2nd Semester</td>
                <td style="width: 140px; font-weight: 600; text-align: center">3rd Semester</td>
            </tr>
            <tr>
                <td>&nbsp;</td>
                <td style="text-align: center; font-weight: bold"><b>Numeric Grade</b></td>
                <td style="text-align: center; font-weight: bold"><b>Numeric Grade</b></td>
                <td style="text-align: center; font-weight: bold"><b>Numeric Grade</b></td>
            </tr>
            <tr>
                <td>@Html.TextBox("CourseName1", "Math")</td>
                <td style="text-align: center">@Html.TextBox("Course1Sem1NumericGrade", "0", new { style = "width: 60px;" })</td>
                <td style="text-align: center">@Html.TextBox("Course1Sem2NumericGrade", "0", new { style = "width: 60px;" })</td>
                <td style="text-align: center">@Html.TextBox("Course1Sem3NumericGrade", "0", new { style = "width: 60px;" })</td>
            </tr>
            <tr>
                <td>@Html.TextBox("CourseName2", "English")</td>
                <td style="text-align: center">@Html.TextBox("Course2Sem1NumericGrade", "0", new { style = "width: 60px;" })</td>
                <td style="text-align: center">@Html.TextBox("Course2Sem2NumericGrade", "0", new { style = "width: 60px;" })</td>
                <td style="text-align: center">@Html.TextBox("Course2Sem3NumericGrade", "0", new { style = "width: 60px;" })</td>
            </tr>
            <tr>
                <td>@Html.TextBox("CourseName3", "Social Science")</td>
                <td style="text-align: center">@Html.TextBox("Course3Sem1NumericGrade", "0", new { style = "width: 60px;" })</td>
                <td style="text-align: center">@Html.TextBox("Course3Sem2NumericGrade", "0", new { style = "width: 60px;" })</td>
                <td style="text-align: center">@Html.TextBox("Course3Sem3NumericGrade", "0", new { style = "width: 60px;" })</td>
            </tr>
            <tr>
                <td>@Html.TextBox("CourseName4", "Physical Science")</td>
                <td style="text-align: center">@Html.TextBox("Course4Sem1NumericGrade", "0", new { style = "width: 60px;" })</td>
                <td style="text-align: center">@Html.TextBox("Course4Sem2NumericGrade", "0", new { style = "width: 60px;" })</td>
                <td style="text-align: center">@Html.TextBox("Course4Sem3NumericGrade", "0", new { style = "width: 60px;" })</td>
            </tr>
            <tr>
                <td>@Html.TextBox("CourseName5", "History/Geography")</td>
                <td style="text-align: center">@Html.TextBox("Course5Sem1NumericGrade", "0", new { style = "width: 60px;" })</td>
                <td style="text-align: center">@Html.TextBox("Course5Sem2NumericGrade", "0", new { style = "width: 60px;" })</td>
                <td style="text-align: center">@Html.TextBox("Course5Sem3NumericGrade", "0", new { style = "width: 60px;" })</td>
            </tr>
        </table>
        <hr />
        <p style="width: 600px; text-align: center"><input type="submit" name="btnPrepareGradeReport" value="Prepare Grade Report" style="width: 300px" /></p>
    }

20. Click the AcademicsController.cs tab and add some arguments to the GradeReportPreparation() method as follows:

    using System;
    using System.Web.Mvc;
    
    namespace RedOakHighSchool1.Controllers
    {
        public class AcademicsController : Controller
        {
            // GET: Academics
            public ActionResult Index()
            {
                return View();
            }
    
            // GET: Academics/StartGradeReport
            public ActionResult StartGradeReport()
            {
                return View();
            }
    
            // GET: Academics/GradeReportPreparation
            public ActionResult GradeReportPreparation(string CourseName1, string Course1Sem1NumericGrade, string Course1Sem2NumericGrade, string Course1Sem3NumericGrade,
                                                       string CourseName2, string Course2Sem1NumericGrade, string Course2Sem2NumericGrade, string Course2Sem3NumericGrade,
                                                       string CourseName3, string Course3Sem1NumericGrade, string Course3Sem2NumericGrade, string Course3Sem3NumericGrade,
                                                       string CourseName4, string Course4Sem1NumericGrade, string Course4Sem2NumericGrade, string Course4Sem3NumericGrade,
                                                       string CourseName5, string Course5Sem1NumericGrade, string Course5Sem2NumericGrade, string Course5Sem3NumericGrade)
            {
                return View();
            }
        }
    }

Creating a Functional Task

To create a task, declare a variable of the Task<> class. As seen when studying generics, you must specify the parameter type. In this case, this is the type returned by the function. The parameter type can be a primitive (number-based, character, Boolean) or a string. It can also be a class type.

To let you initialize a task, the Task<> class is equipped with various constructors. The simples constructor uses the following syntax:

public Task(Func<TResult> function);

This constructor takes a function (a method that returns a value) as argument. The function doesn't take any argument but it must return any value you want. You can first define a method and pass its name as the argument to the above constructor. Here is an example:

using System.Web.Mvc;
using System.Threading.Tasks;

namespace RedOakHighSchool1.Controllers
{
    public class AcademicsController : Controller
    {
        private int number = 88;

        // GET: Academics
        public ActionResult Index()
        {
            return View();
        }

        // GET: Academics/StartGradeReport
        public ActionResult StartGradeReport()
        {
            return View();
        }

        // GET: Academics/GradeReportPreparation
        public ActionResult GradeReportPreparation()
        {
            Task<char> courseGradeProcessing = new Task<char>(GetLetterGrade);

            return View();
        }

        public char GetLetterGrade()
        {
            if (number >= 90)
                return 'A';
            else if (number >= 80)
                return 'B';
            else if (number >= 70)
                return 'C';
            else if (number >= 65)
                return 'D';

            return 'F';
        }
    }
}

Alternatively, you can define the function as a Func<> object and then pass its name to the constructor. Here is an example:

using System;
using System.Web.Mvc;
using System.Threading.Tasks;

namespace RedOakHighSchool1.Controllers
{
    public class AcademicsController : Controller
    {
        // GET: Academics
        public ActionResult Index()
        {
            return View();
        }

        // GET: Academics/StartGradeReport
        public ActionResult StartGradeReport()
        {
            return View();
        }

        // GET: Academics/GradeReportPreparation
        public ActionResult GradeReportPreparation()
        {
            int number = 88;

            Func<char> GetLetterGrade = () =>
            {
                if (number >= 90)
                    return 'A';
                else if (number >= 80)
                    return 'B';
                else if (number >= 70)
                    return 'C';
                else if (number >= 65)
                    return 'D';

                return 'F';
            };

            Task<char> courseGradeProcessing = new Task<char>(GetLetterGrade);

            return View();
        }
    }
}

One more option is to define the function as a lambda expression in the parentheses of the constructor.

Practical Learning: Creating Tasks

• Change the AcademicsController.cs document as follows:

  using System;
  using System.Web.Mvc;
  using System.Threading.Tasks;
  
  namespace RedOakHighSchool1.Controllers
  {
      public class AcademicsController : Controller
      {
          private int number = -1;
  
          // GET: Academics
          public ActionResult Index()
          {
              return View();
          }
  
          // GET: Academics/StartGradeReport
          public ActionResult StartGradeReport()
          {
              return View();
          }
  
          // GET: Academics/GradeReportPreparation
          public ActionResult GradeReportPreparation(string CourseName1, string Course1Sem1NumericGrade, string Course1Sem2NumericGrade, string Course1Sem3NumericGrade,
                                                     string CourseName2, string Course2Sem1NumericGrade, string Course2Sem2NumericGrade, string Course2Sem3NumericGrade,
                                                     string CourseName3, string Course3Sem1NumericGrade, string Course3Sem2NumericGrade, string Course3Sem3NumericGrade,
                                                     string CourseName4, string Course4Sem1NumericGrade, string Course4Sem2NumericGrade, string Course4Sem3NumericGrade,
                                                     string CourseName5, string Course5Sem1NumericGrade, string Course5Sem2NumericGrade, string Course5Sem3NumericGrade)
          {
              number = int.Parse(Course1Sem1NumericGrade);
              int iCourse2Sem1NumericGrade = int.Parse(Course2Sem1NumericGrade);
              int iCourse3Sem1NumericGrade = int.Parse(Course3Sem1NumericGrade);
  
              Func<char> GetCourse2LetterGrade = () =>
              {
                  if (iCourse2Sem1NumericGrade >= 90)
                      return 'A';
                  else if (iCourse2Sem1NumericGrade >= 80)
                      return 'B';
                  else if (iCourse2Sem1NumericGrade >= 70)
                      return 'C';
                  else if (iCourse2Sem1NumericGrade >= 65)
                      return 'D';
  
                  return 'F';
              };
  
              Task<char> processCourse1Sem1NumericGrade = new Task<char>(GetCourse1LetterGrade);
              Task<char> processCourse2Sem1NumericGrade = new Task<char>(GetCourse2LetterGrade);
  
              Task<char> processCourse3Sem1NumericGrade = new Task<char>(() =>
              {
                  if (iCourse3Sem1NumericGrade >= 90)
                      return 'A';
                  else if (iCourse3Sem1NumericGrade >= 80)
                      return 'B';
                  else if (iCourse3Sem1NumericGrade >= 70)
                      return 'C';
                  else if (iCourse3Sem1NumericGrade >= 65)
                      return 'D';
  
                  return 'F';
              });
  
              return View();
          }
  
          public char GetCourse1LetterGrade()
          {
              if (number >= 90)
                  return 'A';
              else if (number >= 80)
                  return 'B';
              else if (number >= 70)
                  return 'C';
              else if (number >= 65)
                  return 'D';
  
              return 'F';
          }
      }
  }

Introduction to Starting a Functional Task

After creating a task, there are many ways you can launch it. As one way to do this, and as seen for the Task class, the Task<> class inherits the Start() method from its parent.

Practical Learning: Starting a Functional Task

1. Change the GradeReportPreparation() method as follows:

   using System;
   using System.Web.Mvc;
   using System.Threading.Tasks;
   
   namespace RedOakHighSchool1.Controllers
   {
       public class AcademicsController : Controller
       {
           private int number = -1;
   
           // GET: Academics
           public ActionResult Index()
           {
               return View();
           }
   
           // GET: Academics/StartGradeReport
           public ActionResult StartGradeReport()
           {
               return View();
           }
   
           // GET: Academics/GradeReportPreparation
           public ActionResult GradeReportPreparation(string CourseName1, string Course1Sem1NumericGrade, string Course1Sem2NumericGrade, string Course1Sem3NumericGrade,
                                                      string CourseName2, string Course2Sem1NumericGrade, string Course2Sem2NumericGrade, string Course2Sem3NumericGrade,
                                                      string CourseName3, string Course3Sem1NumericGrade, string Course3Sem2NumericGrade, string Course3Sem3NumericGrade,
                                                      string CourseName4, string Course4Sem1NumericGrade, string Course4Sem2NumericGrade, string Course4Sem3NumericGrade,
                                                      string CourseName5, string Course5Sem1NumericGrade, string Course5Sem2NumericGrade, string Course5Sem3NumericGrade)
           {
               number = int.Parse(Course1Sem1NumericGrade);
               int iCourse2Sem1NumericGrade = int.Parse(Course2Sem1NumericGrade);
               int iCourse3Sem1NumericGrade = int.Parse(Course3Sem1NumericGrade);
   
               Func<char> GetCourse2LetterGrade = () =>
               {
                   if (iCourse2Sem1NumericGrade >= 90)
                       return 'A';
                   else if (iCourse2Sem1NumericGrade >= 80)
                       return 'B';
                   else if (iCourse2Sem1NumericGrade >= 70)
                       return 'C';
                   else if (iCourse2Sem1NumericGrade >= 65)
                       return 'D';
   
                   return 'F';
               };
   
               Task<char> processCourse1Sem1NumericGrade = new Task<char>(GetCourse1LetterGrade);
               Task<char> processCourse2Sem1NumericGrade = new Task<char>(GetCourse2LetterGrade);
   
               Task<char> processCourse3Sem1NumericGrade = new Task<char>(() =>
               {
                   if (iCourse3Sem1NumericGrade >= 90)
                       return 'A';
                   else if (iCourse3Sem1NumericGrade >= 80)
                       return 'B';
                   else if (iCourse3Sem1NumericGrade >= 70)
                       return 'C';
                   else if (iCourse3Sem1NumericGrade >= 65)
                       return 'D';
   
                   return 'F';
               });
   
               processCourse1Sem1NumericGrade.Start();
               processCourse2Sem1NumericGrade.Start();
               processCourse3Sem1NumericGrade.Start();
   
               return View();
           }
   
           private char GetCourse1LetterGrade()
           {
               if (number >= 90)
                   return 'A';
               else if (number >= 80)
                   return 'B';
               else if (number >= 70)
                   return 'C';
               else if (number >= 65)
                   return 'D';
   
               return 'F';
           }
       }
   }

The Value of a Functional Task

Remember that, unlike the Task object, a Task<int> produces a value. To let you get that value, the Task<int> class is equipped with a property named Result:

public TResult Result { get; }

Practical Learning: Getting the Result of a Task

1. Change the GradeReportPreparation() method as follows:

   using System;
   using System.Web.Mvc;
   using System.Threading.Tasks;
   
   namespace RedOakHighSchool1.Controllers
   {
       public class AcademicsController : Controller
       {
           private int number = -1;
   
           // GET: Academics
           public ActionResult Index()
           {
               return View();
           }
   
           // GET: Academics/StartGradeReport
           public ActionResult StartGradeReport()
           {
               return View();
           }
   
           // GET: Academics/GradeReportPreparation
           public ActionResult GradeReportPreparation(string CourseName1, string Course1Sem1NumericGrade, string Course1Sem2NumericGrade, string Course1Sem3NumericGrade,
                                                      string CourseName2, string Course2Sem1NumericGrade, string Course2Sem2NumericGrade, string Course2Sem3NumericGrade,
                                                      string CourseName3, string Course3Sem1NumericGrade, string Course3Sem2NumericGrade, string Course3Sem3NumericGrade,
                                                      string CourseName4, string Course4Sem1NumericGrade, string Course4Sem2NumericGrade, string Course4Sem3NumericGrade,
                                                      string CourseName5, string Course5Sem1NumericGrade, string Course5Sem2NumericGrade, string Course5Sem3NumericGrade)
           {
   
               number = int.Parse(Course1Sem1NumericGrade);
               int iCourse2Sem1NumericGrade = int.Parse(Course2Sem1NumericGrade);
               int iCourse3Sem1NumericGrade = int.Parse(Course3Sem1NumericGrade);
   
               Func<char> GetCourse2LetterGrade = () =>
               {
                   if (iCourse2Sem1NumericGrade >= 90)
                       return 'A';
                   else if (iCourse2Sem1NumericGrade >= 80)
                       return 'B';
                   else if (iCourse2Sem1NumericGrade >= 70)
                       return 'C';
                   else if (iCourse2Sem1NumericGrade >= 65)
                       return 'D';
   
                   return 'F';
               };
   
   
               Task<char> processCourse1Sem1NumericGrade = new Task<char>(GetCourse1LetterGrade);
               Task<char> processCourse2Sem1NumericGrade = new Task<char>(GetCourse2LetterGrade);
   
               Task<char> processCourse3Sem1NumericGrade = new Task<char>(() =>
               {
                   if (iCourse3Sem1NumericGrade >= 90)
                       return 'A';
                   else if (iCourse3Sem1NumericGrade >= 80)
                       return 'B';
                   else if (iCourse3Sem1NumericGrade >= 70)
                       return 'C';
                   else if (iCourse3Sem1NumericGrade >= 65)
                       return 'D';
   
                   return 'F';
               });
   
               processCourse1Sem1NumericGrade.Start();
               processCourse2Sem1NumericGrade.Start();
               processCourse3Sem1NumericGrade.Start();
   
               ViewBag.Course1Sem1LetterGrade = processCourse1Sem1NumericGrade.Result;
               ViewBag.Course2Sem1LetterGrade = processCourse2Sem1NumericGrade.Result;
               ViewBag.Course3Sem1LetterGrade = processCourse3Sem1NumericGrade.Result;
   
               return View();
           }
   
           public char GetCourse1LetterGrade()
           {
               if (number >= 90)
                   return 'A';
               else if (number >= 80)
                   return 'B';
               else if (number >= 70)
                   return 'C';
               else if (number >= 65)
                   return 'D';
   
               return 'F';
           }
       }
   }

2. Click the GradeReportPreparation.cshtml tab and change it as follows:

   @{
       ViewBag.Title = "Grade Report Preparation";
   }
   
   <h1>Red Oak High School</h1>
   <h2>Grade Report Preparation</h2>
   
   @{
       char cCourse1Sem1LetterGrade = ViewBag.Course1Sem1LetterGrade;
       char cCourse2Sem1LetterGrade = ViewBag.Course2Sem1LetterGrade;
       char cCourse3Sem1LetterGrade = ViewBag.Course3Sem1LetterGrade;
   }
   
   @using (Html.BeginForm())
   {
       <table border="6">
           <tr>
               <td><b>Course Name</b></td>
               <td colspan="2" style="width: 140px; font-weight: 600; text-align: center">1st Semester</td>
               <td colspan="2" style="width: 140px; font-weight: 600; text-align: center">2nd Semester</td>
               <td colspan="2" style="width: 140px; font-weight: 600; text-align: center">3rd Semester</td>
           </tr>
           <tr>
               <td>&nbsp;</td>
               <td style="text-align: center; font-weight: 600;">Num Grd</td>
               <td style="text-align: center; font-weight: 600;">Ltr Grd</td>
               <td style="text-align: center; font-weight: 600;">Num Grd</td>
               <td style="text-align: center; font-weight: 600;">Ltr Grd</td>
               <td style="text-align: center; font-weight: 600;">Num Grd</td>
               <td style="text-align: center; font-weight: 600;">Ltr Grd</td>
           </tr>
           <tr>
               <td style="text-align: center">@Html.TextBox("CourseName1", @"CourseName1")</td>
               <td style="text-align: center">@Html.TextBox("Course1Sem1NumericGrade", @"Course1Sem1NumericGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course1Sem1LetterGrade", @cCourse1Sem1LetterGrade, new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course1Sem2NumericGrade", "Course1Sem2NumericGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course1Sem2LetterGrade", "Course1Sem2LetterGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course1Sem3NumericGrade", "Course1Sem3NumericGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course1Sem3LetterGrade", "Course1Sem3LetterGrade", new { style = "width: 60px;" })</td>
           </tr>
           <tr>
               <td style="text-align: center">@Html.TextBox("CourseName2", @"CourseName2")</td>
               <td style="text-align: center">@Html.TextBox("Course2Sem1NumericGrade", @"Course2Sem1NumericGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course2Sem1LetterGrade", @cCourse2Sem1LetterGrade, new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course2Sem2NumericGrade", "Course2Sem2NumericGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course2Sem2LetterGrade", "Course2Sem2LetterGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course2Sem3NumericGrade", "Course2Sem3NumericGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course2Sem3LetterGrade", "Course2Sem3LetterGrade", new { style = "width: 60px;" })</td>
           </tr>
           <tr>
               <td style="text-align: center">@Html.TextBox("CourseName3", @"CourseName3")</td>
               <td style="text-align: center">@Html.TextBox("Course3Sem1NumericGrade", @"Course3Sem1NumericGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course3Sem1LetterGrade", @cCourse3Sem1LetterGrade, new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course3Sem2NumericGrade", "Course3Sem2NumericGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course3Sem2LetterGrade", "Course3Sem2LetterGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course3Sem3NumericGrade", "Course3Sem3NumericGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course3Sem3LetterGrade", "Course3Sem3LetterGrade", new { style = "width: 60px;" })</td>
           </tr>
           <tr>
               <td style="text-align: center">@Html.TextBox("CourseName4", @"CourseName4")</td>
               <td style="text-align: center">@Html.TextBox("Course4Sem1NumericGrade", @"Course4Sem1NumericGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course4Sem1LetterGrade", "Course4Sem1LetterGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course4Sem2NumericGrade", "Course4Sem2NumericGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course4Sem2LetterGrade", "Course4Sem2LetterGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course4Sem3NumericGrade", "Course4Sem3NumericGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course4Sem3LetterGrade", "Course4Sem3LetterGrade", new { style = "width: 60px;" })</td>
           </tr>
           <tr>
               <td style="text-align: center">@Html.TextBox("CourseName5", @"CourseName5")</td>
               <td style="text-align: center">@Html.TextBox("Course5Sem1NumericGrade", @"Course5Sem1NumericGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course5Sem1LetterGrade", "Course5Sem1LetterGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course5Sem2NumericGrade", "Course5Sem2NumericGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course5Sem2LetterGrade", "Course5Sem2LetterGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course5Sem3NumericGrade", "Course5Sem3NumericGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course5Sem3LetterGrade", "Course5Sem3LetterGrade", new { style = "width: 60px;" })</td>
           </tr>
       </table>
       <hr />
   }

3. Click the GradeReportStartUp.cshtml tab to activate it

4. To execute the application, on the main menu, click Debug -> Start Without Debugging:

   

5. On the form, change Math to Algebra 1
6. Change some values as follows:

   Course Name	1st Semester
                Numeric Grade
   Algebra 1	       92
   English		   64
   Social Science   88

   

7. Click the Prepare Grade Report button:

   

8. Close the browser and return to your programming environment

Running a Functional Task<>

The Task<> class inherits the Run() method from its parent. This gives you various ways to immediately (create and) start a task. When it comes to a generic task, if you want, you can specify the parameter type on the Task object and/or the Run() method.

Practical Learning: Running a Task

1. Click the AcademicsController.cs tab and change the document as follows:

   using System;
   using System.Collections.Generic;
   using System.Linq;
   using System.Web.Mvc;
   using System.Threading.Tasks;
   
   namespace RedOakHighSchool1.Controllers
   {
       public class AcademicsController : Controller
       {
           private int number = -1;
   
           // GET: Academics
           public ActionResult Index()
           {
               return View();
           }
   
           // GET: Academics/StartGradeReport
           public ActionResult StartGradeReport()
           {
               return View();
           }
   
           // GET: Academics/GradeReportPreparation
           public ActionResult GradeReportPreparation(string CourseName1, string Course1Sem1NumericGrade, string Course1Sem2NumericGrade, string Course1Sem3NumericGrade,
                                                      string CourseName2, string Course2Sem1NumericGrade, string Course2Sem2NumericGrade, string Course2Sem3NumericGrade,
                                                      string CourseName3, string Course3Sem1NumericGrade, string Course3Sem2NumericGrade, string Course3Sem3NumericGrade,
                                                      string CourseName4, string Course4Sem1NumericGrade, string Course4Sem2NumericGrade, string Course4Sem3NumericGrade,
                                                      string CourseName5, string Course5Sem1NumericGrade, string Course5Sem2NumericGrade, string Course5Sem3NumericGrade)
           {
   
               number = int.Parse(Course1Sem1NumericGrade);
               int iCourse2Sem1NumericGrade = int.Parse(Course2Sem1NumericGrade);
               int iCourse3Sem1NumericGrade = int.Parse(Course3Sem1NumericGrade);
   
               Func<char> GetCourse2LetterGrade = () =>
               {
                   if (iCourse2Sem1NumericGrade >= 90)
                       return 'A';
                   else if (iCourse2Sem1NumericGrade >= 80)
                       return 'B';
                   else if (iCourse2Sem1NumericGrade >= 70)
                       return 'C';
                   else if (iCourse2Sem1NumericGrade >= 65)
                       return 'D';
   
                   return 'F';
               };
   
               Task<char> processCourse1Sem1NumericGrade = new Task<char>(GetCourse1LetterGrade);
               Task<char> processCourse2Sem1NumericGrade = new Task<char>(GetCourse2LetterGrade);
   
               Task<char> processCourse3Sem1NumericGrade = new Task<char>(() =>
               {
                   if (iCourse3Sem1NumericGrade >= 90)
                       return 'A';
                   else if (iCourse3Sem1NumericGrade >= 80)
                       return 'B';
                   else if (iCourse3Sem1NumericGrade >= 70)
                       return 'C';
                   else if (iCourse3Sem1NumericGrade >= 65)
                       return 'D';
   
                   return 'F';
               });
   
               processCourse1Sem1NumericGrade.Start();
               processCourse2Sem1NumericGrade.Start();
               processCourse3Sem1NumericGrade.Start();
   
               ViewBag.Course1Sem1LetterGrade = processCourse1Sem1NumericGrade.Result;
               ViewBag.Course2Sem1LetterGrade = processCourse2Sem1NumericGrade.Result;
               ViewBag.Course3Sem1LetterGrade = processCourse3Sem1NumericGrade.Result;
   
               int iCourse4Sem1NumericGrade = int.Parse(Course4Sem1NumericGrade);
               int iCourse5Sem1NumericGrade = int.Parse(Course5Sem1NumericGrade);
   
   	    Func<char> GetCourse4LetterGrade = () =>
               {
                   if (iCourse4Sem1NumericGrade >= 90)
                       return 'A';
                   else if (iCourse4Sem1NumericGrade >= 80)
                       return 'B';
                   else if (iCourse4Sem1NumericGrade >= 70)
                       return 'C';
                   else if (iCourse4Sem1NumericGrade >= 65)
                       return 'D';
   
                   return 'F';
               };
   
               Task<char> processCourse4Sem1NumericGrade = Task<char>.Run<char>(GetCourse4LetterGrade);
               Task<char> processCourse5Sem1NumericGrade = Task<char>.Run<char>(() =>
               {
                   if (iCourse5Sem1NumericGrade >= 90)
                       return 'A';
                   else if (iCourse5Sem1NumericGrade >= 80)
                       return 'B';
                   else if (iCourse5Sem1NumericGrade >= 70)
                       return 'C';
                   else if (iCourse5Sem1NumericGrade >= 65)
                       return 'D';
   
                   return 'F';
               });
   
               ViewBag.Course4Sem1LetterGrade = processCourse4Sem1NumericGrade.Result;
               ViewBag.Course5Sem1LetterGrade = processCourse5Sem1NumericGrade.Result;
   
               return View();
           }
   
           public char GetCourse1LetterGrade()
           {
               if (number >= 90)
                   return 'A';
               else if (number >= 80)
                   return 'B';
               else if (number >= 70)
                   return 'C';
               else if (number >= 65)
                   return 'D';
   
               return 'F';
           }
   
       }
   }

2. Access the GradeReportPreparation.cshtml tab and change its document as follows:

   @{
       ViewBag.Title = "Grade Report Preparation";
   }
   
   <h1>Red Oak High School</h1>
   <h2>Grade Report Preparation</h2>
   
   @{
       char cCourse1Sem1LetterGrade = ViewBag.Course1Sem1LetterGrade;
       char cCourse2Sem1LetterGrade = ViewBag.Course2Sem1LetterGrade;
       char cCourse3Sem1LetterGrade = ViewBag.Course3Sem1LetterGrade;
       char cCourse4Sem1LetterGrade = ViewBag.Course4Sem1LetterGrade;
       char cCourse5Sem1LetterGrade = ViewBag.Course5Sem1LetterGrade;
   }
   
   @using (Html.BeginForm())
   {
       <table border="6">
           <tr>
               <td><b>Course Name</b></td>
               <td colspan="2" style="width: 140px; font-weight: 600; text-align: center">1st Semester</td>
               <td colspan="2" style="width: 140px; font-weight: 600; text-align: center">2nd Semester</td>
               <td colspan="2" style="width: 140px; font-weight: 600; text-align: center">3rd Semester</td>
           </tr>
           <tr>
               <td>&nbsp;</td>
               <td style="text-align: center; font-weight: 600;">Num Grd</td>
               <td style="text-align: center; font-weight: 600;">Ltr Grd</td>
               <td style="text-align: center; font-weight: 600;">Num Grd</td>
               <td style="text-align: center; font-weight: 600;">Ltr Grd</td>
               <td style="text-align: center; font-weight: 600;">Num Grd</td>
               <td style="text-align: center; font-weight: 600;">Ltr Grd</td>
           </tr>
           <tr>
               <td style="text-align: center">@Html.TextBox("CourseName1", @"CourseName1")</td>
               <td style="text-align: center">@Html.TextBox("Course1Sem1NumericGrade", @"Course1Sem1NumericGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course1Sem1LetterGrade", @cCourse1Sem1LetterGrade, new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course1Sem2NumericGrade", "Course1Sem2NumericGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course1Sem2LetterGrade", "Course1Sem2LetterGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course1Sem3NumericGrade", "Course1Sem3NumericGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course1Sem3LetterGrade", "Course1Sem3LetterGrade", new { style = "width: 60px;" })</td>
           </tr>
           <tr>
               <td style="text-align: center">@Html.TextBox("CourseName2", @"CourseName2")</td>
               <td style="text-align: center">@Html.TextBox("Course2Sem1NumericGrade", @"Course2Sem1NumericGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course2Sem1LetterGrade", @cCourse2Sem1LetterGrade, new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course2Sem2NumericGrade", "Course2Sem2NumericGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course2Sem2LetterGrade", "Course2Sem2LetterGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course2Sem3NumericGrade", "Course2Sem3NumericGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course2Sem3LetterGrade", "Course2Sem3LetterGrade", new { style = "width: 60px;" })</td>
           </tr>
           <tr>
               <td style="text-align: center">@Html.TextBox("CourseName3", @"CourseName3")</td>
               <td style="text-align: center">@Html.TextBox("Course3Sem1NumericGrade", @"Course3Sem1NumericGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course3Sem1LetterGrade", @cCourse3Sem1LetterGrade, new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course3Sem2NumericGrade", "Course3Sem2NumericGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course3Sem2LetterGrade", "Course3Sem2LetterGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course3Sem3NumericGrade", "Course3Sem3NumericGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course3Sem3LetterGrade", "Course3Sem3LetterGrade", new { style = "width: 60px;" })</td>
           </tr>
           <tr>
               <td style="text-align: center">@Html.TextBox("CourseName4", @"CourseName4")</td>
               <td style="text-align: center">@Html.TextBox("Course4Sem1NumericGrade", @"Course4Sem1NumericGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course4Sem1LetterGrade", @cCourse4Sem1LetterGrade, new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course4Sem2NumericGrade", "Course4Sem2NumericGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course4Sem2LetterGrade", "Course4Sem2LetterGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course4Sem3NumericGrade", "Course4Sem3NumericGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course4Sem3LetterGrade", "Course4Sem3LetterGrade", new { style = "width: 60px;" })</td>
           </tr>
           <tr>
               <td style="text-align: center">@Html.TextBox("CourseName5", @"CourseName5")</td>
               <td style="text-align: center">@Html.TextBox("Course5Sem1NumericGrade", @"Course5Sem1NumericGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course5Sem1LetterGrade", @cCourse5Sem1LetterGrade, new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course5Sem2NumericGrade", "Course5Sem2NumericGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course5Sem2LetterGrade", "Course5Sem2LetterGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course5Sem3NumericGrade", "Course5Sem3NumericGrade", new { style = "width: 60px;" })</td>
               <td style="text-align: center">@Html.TextBox("Course5Sem3LetterGrade", "Course5Sem3LetterGrade", new { style = "width: 60px;" })</td>
           </tr>
       </table>
       <hr />
   }

3. Click the GradeReportStartUp.cshtml tab to activate it
4. To execute the project, on the main menu, click Debug -> Start Without Debugging
5. On the form, replace Social Science with Philosophy
6. On the form, replace Physical Science with Chemistry
7. Change the grades as follows:

   Course Name	1st Semester
                 Numeric Grade
   Math			    73
   English			96
   Philosophy		92
   Chemistry		    69
   History/Geography	85

   

8. Click the Prepare Grade Report button

   

9. Close the browser and return to your programming environment
10. Close your programming environment

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