c# Task任务的取消方式

        public void ThrowIfCancellationRequested()
        {
            if (IsCancellationRequested) 
                ThrowOperationCanceledException();
        }

using System;
using System.Threading;
using System.Threading.Tasks;

class Program
{
    static async Task Main()
    {
        var tokenSource2 = new CancellationTokenSource();
        CancellationToken ct = tokenSource2.Token;
        var tokenSource3 = new CancellationTokenSource();

        var task = Task.Run(() =>
        {
            // Were we already canceled?
            ct.ThrowIfCancellationRequested();
            
            bool moreToDo = true;
            while (moreToDo)
            {
                // Poll on this property if you have to do
                // other cleanup before throwing.
                // Clean up here, then...
                if(ct.IsCancellationRequested)
                {
                    ct.ThrowIfCancellationRequested();
                }
            }
        },tokenSource2.Token); // Pass same token to Task.Run.

        Thread.Sleep(5000);
        tokenSource2.Cancel();

        // Just continue on this thread, or await with try-catch:
        try
        {
            await task;
        }
        catch (OperationCanceledException e)
        {
            Console.WriteLine($"{nameof(OperationCanceledException)} thrown with message: {e.Message}");
            bool eqs = e.CancellationToken.Equals(tokenSource3.Token);
            System.Console.WriteLine($"Equals' result: {eqs}.");
            System.Console.WriteLine($"Task's status: {task.Status}");
        }
        catch (Exception ex)
        {
            System.Console.WriteLine(ex.Message);
        }
        finally
        {
            tokenSource2.Dispose();
        }

        Console.ReadKey();
    }
}
/*
The operation was canceled.
OperationCanceledException thrown with message: The operation was canceled.
Equals' result: False.
Task's status: Canceled
*/

},tokenSource3.Token); // Pass same token to Task.Run.