C# Language
Task Parallele Bibliothek
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Parallel.ForEach
Ein Beispiel, das die Parallel.ForEach-Schleife verwendet, um ein bestimmtes Array von Website-URLs zu pingen.
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.für
Ein Beispiel, in dem die Parallel.For-Schleife zum Pingen eines angegebenen Arrays von Website-URLs verwendet wird.
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.Einruf
Paralleles Aufrufen von Methoden oder Aktionen (Paralleler Bereich)
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));
}
}
Eine async-stornierbare Abrufaufgabe, die zwischen Iterationen wartet
public class Foo
{
private const int TASK_ITERATION_DELAY_MS = 1000;
private CancellationTokenSource _cts;
public Foo()
{
this._cts = new CancellationTokenSource();
}
public void StartExecution()
{
Task.Factory.StartNew(this.OwnCodeCancelableTask_EveryNSeconds, this._cts.Token);
}
public void CancelExecution()
{
this._cts.Cancel();
}
/// <summary>
/// "Infinite" loop that runs every N seconds. Good for checking for a heartbeat or updates.
/// </summary>
/// <param name="taskState">The cancellation token from our _cts field, passed in the StartNew call</param>
private async void OwnCodeCancelableTask_EveryNSeconds(object taskState)
{
var token = (CancellationToken)taskState;
while (!token.IsCancellationRequested)
{
Console.WriteLine("Do the work that needs to happen every N seconds in this loop");
// Passing token here allows the Delay to be cancelled if your task gets cancelled.
await Task.Delay(TASK_ITERATION_DELAY_MS, token);
}
}
}
Eine stornierbare Abfrageaufgabe mit der CancellationTokenSource
public class Foo
{
private CancellationTokenSource _cts;
public Foo()
{
this._cts = new CancellationTokenSource();
}
public void StartExecution()
{
Task.Factory.StartNew(this.OwnCodeCancelableTask, this._cts.Token);
}
public void CancelExecution()
{
this._cts.Cancel();
}
/// <summary>
/// "Infinite" loop with no delays. Writing to a database while pulling from a buffer for example.
/// </summary>
/// <param name="taskState">The cancellation token from our _cts field, passed in the StartNew call</param>
private void OwnCodeCancelableTask(object taskState)
{
var token = (CancellationToken) taskState; //Our cancellation token passed from StartNew();
while ( !token.IsCancellationRequested )
{
Console.WriteLine("Do your task work in this loop");
}
}
}
Async-Version von 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;
}
Modified text is an extract of the original Stack Overflow Documentation
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