An Async/Await example in C# where we have a console application startup method calling the TaskRunner.ProcessAsync() static method to initiate and kick off the async Tasks.
Not all classes are shown below, but just a subset, for brevity.
public class Program
{
public static void Main()
{
Console.WriteLine(Utility.GenerateOutputMessage("ProcessTasks.ProcessAllAsync", Utility.StepStarted));
TaskRunner.ProcessAsync().Wait();
Console.WriteLine(Utility.GenerateOutputMessage("ProcessTasks.ProcessAllAsync", Utility.StepDone));
Console.WriteLine(@"Press any key to continue...");
Console.ReadKey(true);
}
}The TaskRunner class is responsible for setting up the tasks to be run using the Command design pattern.
public class TaskRunner : ITaskRunner
{
public async Task<bool> SaveAll()
{
Console.WriteLine(Utility.GenerateOutputMessage("TaskRunnerSaveAll", Utility.StepStarted));
// simulate a save routine by adding a little delay
await Task.Delay(2000);
Console.WriteLine(Utility.GenerateOutputMessage("TaskRunnerSaveAll", Utility.StepDone));
return true;
}
public async Task ProcessAsync()
{
// use Command pattern to execute tasks
var taskManager = new TaskManager();
// iterate through and simulate 10 iterations of tasks to run
for (var i = 1; i <= 5; i++)
{
taskManager.AddTaskAsync(new DoTask1(i, 5000));
taskManager.AddTaskAsync(new DoTask2(i, 3000));
}
// create fake people and add to the tasks to run
for (var i = 1; i <= 10; i++)
{
var fakePerson = new FakePerson()
{
FullName = Faker.Name.FullName()
};
taskManager.AddTaskAsync(new FakePersonRepository(i, 200, fakePerson));
}
// wait until all tasks are done executing
await Task.WhenAll(taskManager.RunTasksAsync());
// simulate a batch save
await SaveAll();
}
}The TaskManager class accepts a task to manage, then provides a method to run all the tasks in an async manner.
public class TaskManager : ITaskManager
{
private readonly List<IDoTaskAsync> _tasks = new List<IDoTaskAsync>();
public void AddTaskAsync(IDoTaskAsync task)
{
_tasks.Add(task);
}
public async Task<bool> RunTasksAsync()
{
foreach (var task in _tasks)
{
await task.RunAsync();
}
_tasks.Clear();
return _tasks.Count == 0;
}
}An example of one of the Tasks classes (DoTask1 and DoTask2 are identical)
public interface IDoTaskAsync
{
Task<string> RunAsync();
}
public class DoTask1 : TaskBase, IDoTaskAsync
{
private readonly int _delayInMilliseconds;
private readonly int _taskId;
private const string ClassIdentifier = "DoTask1RunAsync";
public DoTask1(int taskId, int delayInMilliseconds)
{
_taskId = taskId;
_delayInMilliseconds = delayInMilliseconds;
}
public async Task<string> RunAsync()
{
return await RunAsyncTask(ClassIdentifier, _taskId, _delayInMilliseconds);
}
}Here is where we fetch our Fake person data...
public class FakePersonRepository : TaskBase, IDoTaskAsync
{
private readonly int _delayInMilliseconds;
private readonly IFakePerson _fakePerson;
private readonly int _taskId;
private const string ClassIdentifier = "FakePersonRepository";
public FakePersonRepository(int taskId, int delayInMilliseconds, IFakePerson fakePerson)
{
_taskId = taskId;
_delayInMilliseconds = delayInMilliseconds;
_fakePerson = fakePerson;
}
public async Task<string> RunAsync()
{
return await RunAsyncTask(
ClassIdentifier,
_taskId,
_delayInMilliseconds,
_fakePerson.FullName);
}
}Our Utility class of helper methods...
public class Utility
{
public static string StepStarted = "started";
public static string StepDone = "done";
public static string GetFormattedDate(DateTime date)
{
return date.ToString("hh:mm:ss.fff tt");
}
public static string GenerateOutputMessage(string taskName, string stepName)
{
return $"{taskName} {stepName.ToLower()} at {GetFormattedDate(DateTime.Now)}";
}
public static string GenerateOutputMessage(string taskName, string stepName, int num, string message)
{
return message != null ?
$"{taskName} {stepName.ToLower()} {num} [Message: {message}] at {GetFormattedDate(DateTime.Now)}" :
$"{taskName} {stepName.ToLower()} {num} at {GetFormattedDate(DateTime.Now)}";
}
public static int GetDelay(int ms)
{
return new Random(ms).Next(0, ms);
}
}The results will look something like this in your command window...
ProcessTasks.ProcessAllAsync started at 08:54:02.943 AM
DoTask1RunAsync started 1 at 08:54:03.329 AM
DoTask1RunAsync done 1 at 08:54:07.856 AM
DoTask2RunAsync started 1 at 08:54:07.858 AM
DoTask2RunAsync done 1 at 08:54:07.864 AM
DoTask1RunAsync started 2 at 08:54:07.864 AM
DoTask1RunAsync done 2 at 08:54:12.138 AM
DoTask2RunAsync started 2 at 08:54:12.138 AM
DoTask2RunAsync done 2 at 08:54:12.156 AM
DoTask1RunAsync started 3 at 08:54:12.156 AM
DoTask1RunAsync done 3 at 08:54:16.430 AM
DoTask2RunAsync started 3 at 08:54:16.430 AM
DoTask2RunAsync done 3 at 08:54:16.448 AM
DoTask1RunAsync started 4 at 08:54:16.448 AM
DoTask1RunAsync done 4 at 08:54:20.717 AM
DoTask2RunAsync started 4 at 08:54:20.717 AM
DoTask2RunAsync done 4 at 08:54:20.735 AM
DoTask1RunAsync started 5 at 08:54:20.735 AM
DoTask1RunAsync done 5 at 08:54:25.010 AM
DoTask2RunAsync started 5 at 08:54:25.010 AM
DoTask2RunAsync done 5 at 08:54:25.028 AM
FakePersonRepository started 1 [Message: Miss Rickie Weber] at 08:54:25.084 AM
FakePersonRepository done 1 [Message: Miss Rickie Weber] at 08:54:25.131 AM
FakePersonRepository started 2 [Message: Giovani Cormier] at 08:54:25.132 AM
FakePersonRepository done 2 [Message: Giovani Cormier] at 08:54:25.174 AM
FakePersonRepository started 3 [Message: Haleigh Kunze] at 08:54:25.174 AM
FakePersonRepository done 3 [Message: Haleigh Kunze] at 08:54:25.217 AM
FakePersonRepository started 4 [Message: Dr. Oran Fahey] at 08:54:25.218 AM
FakePersonRepository done 4 [Message: Dr. Oran Fahey] at 08:54:25.260 AM
FakePersonRepository started 5 [Message: Hassan Schamberger] at 08:54:25.260 AM
FakePersonRepository done 5 [Message: Hassan Schamberger] at 08:54:25.314 AM
FakePersonRepository started 6 [Message: Laron Hauck] at 08:54:25.314 AM
FakePersonRepository done 6 [Message: Laron Hauck] at 08:54:25.357 AM
FakePersonRepository started 7 [Message: Davon Metz] at 08:54:25.357 AM
FakePersonRepository done 7 [Message: Davon Metz] at 08:54:25.399 AM
FakePersonRepository started 8 [Message: Tiara Willms] at 08:54:25.399 AM
FakePersonRepository done 8 [Message: Tiara Willms] at 08:54:25.452 AM
FakePersonRepository started 9 [Message: Freeda Schowalter] at 08:54:25.452 AM
FakePersonRepository done 9 [Message: Freeda Schowalter] at 08:54:25.495 AM
FakePersonRepository started 10 [Message: Estefania Swift] at 08:54:25.497 AM
FakePersonRepository done 10 [Message: Estefania Swift] at 08:54:25.541 AM
TaskRunnerSaveAll started at 08:54:25.543 AM
TaskRunnerSaveAll done at 08:54:27.553 AM
ProcessTasks.ProcessAllAsync done at 08:54:27.553 AM
Press any key to continue...