Task Parallel Library

Parallel.ForEach

An example that uses Parallel.ForEach loop to ping a given array of website urls.

static void Main()
{
    string [] urls = 
    {
        "www.stackoverflow.com", 
        "www.google.net", 
        "www.facebook.com", 
        "www.twitter.com"
    };
    
    System.Threading.Tasks.Parallel.ForEach(urls, url =>
    {
        var ping = new System.Net.NetworkInformation.Ping();

        var result = ping.Send(url);

        if (result.Status == System.Net.NetworkInformation.IPStatus.Success)
        {
            Console.WriteLine(string.Format("{0} is online", url));
        }
    });
}

Parallel.For

An example that uses Parallel.For loop to ping a given array of website urls.

static void Main()
{
    string [] urls = 
    {
        "www.stackoverflow.com", 
        "www.google.net", 
        "www.facebook.com", 
        "www.twitter.com"
    };

    System.Threading.Tasks.Parallel.For(0, urls.Length, i =>
    {
        var ping = new System.Net.NetworkInformation.Ping();

        var result = ping.Send(urls[i]);

        if (result.Status == System.Net.NetworkInformation.IPStatus.Success)
        {
            Console.WriteLine(string.Format("{0} is online", urls[i]));
        }
    });
}

Parallel.Invoke

Invoking methods or actions in parallel (Parallel region)

static void Main()
{
    string [] urls = 
    {
        "www.stackoverflow.com", 
        "www.google.net", 
        "www.facebook.com", 
        "www.twitter.com"
    };
    
    System.Threading.Tasks.Parallel.Invoke(
        () => PingUrl(urls[0]),
        () => PingUrl(urls[1]),
        () => PingUrl(urls[2]),
        () => PingUrl(urls[3])
    );
}

void PingUrl(string url)
{
    var ping = new System.Net.NetworkInformation.Ping();
    
    var result = ping.Send(url);
    
    if (result.Status == System.Net.NetworkInformation.IPStatus.Success)
    {
        Console.WriteLine(string.Format("{0} is online", url));
    }
}

An async cancellable polling Task that waits between iterations

A cancellable polling Task using CancellationTokenSource

Async version of PingUrl

    static void Main(string[] args)
    {
        string url = "www.stackoverflow.com";
        var pingTask = PingUrlAsync(url);
        Console.WriteLine($"Waiting for response from {url}");
        Task.WaitAll(pingTask);            
        Console.WriteLine(pingTask.Result);
    }

    static async Task<string> PingUrlAsync(string url)
    {
        string response = string.Empty;
        var ping = new System.Net.NetworkInformation.Ping();

        var result = await ping.SendPingAsync(url);

        await Task.Delay(5000); //simulate slow internet

        if (result.Status == System.Net.NetworkInformation.IPStatus.Success)
        {
            response = $"{url} is online";
        }

        return response;
    }