[C#] Asynchcronous methods execution examples

AsyncMethods.md

Asynchronous Methods - C# Examples

Below we have a synchronous method that counts to 5.

static void Main(string[] args)
{
  Console.WriteLine("START");
  Count();
  Console.WriteLine("END");
  Console.ReadKey();
}

private static void Count()
{
  for (int i = 0; i < 5; i++)
  {
    Console.WriteLine(i + 1);
  }
  Console.WriteLine("End of count");
}

Output

START
1
2
3
4
5
End of count
END

But some times we don't want to stop the code execution to make something, like counting. In the next examples are shown how the code execution is affected by await, async, Task.Run() and .Wait().

Example 1

static void Main(string[] args)
{
  Console.WriteLine("START");
  CountAsync();
  Console.WriteLine("END");
  Console.ReadKey();
}

private static async Task CountAsync()
{
  Task.Run(() => {
    for (int i = 0; i < 5; i++)
    {
      Console.WriteLine(i + 1);
    }
  });
  Console.WriteLine("End of count");
}

Output

START
End of count
END
1
2
3
4
5

Example 2

static void Main(string[] args)
{
  Console.WriteLine("START");
  CountAsync();
  Console.WriteLine("END");
  Console.ReadKey();
}

private static async Task CountAsync()
{
  await Task.Run(() => {
    for (int i = 0; i < 10; i++)
    {
      Console.WriteLine(i + 1);
    }
  });
  Console.WriteLine("End of count");
}

Output

START
END
1
2
3
4
5
End of count

Example 3

static void Main(string[] args)
{
  Console.WriteLine("START");
  CountAsync().Wait();
  Console.WriteLine("END");
  Console.ReadKey();
}

private static async Task CountAsync()
{
  await Task.Run(() => {
    for (int i = 0; i < 10; i++)
    {
      Console.WriteLine(i + 1);
    }
  });
  Console.WriteLine("End of count");
}

Output

START
1
2
3
4
5
End of count
END