CancellationToken

CancellationToken

CancellationToken provides a cooperative way to signal that a running asynchronous operation should stop early. A CancellationTokenSource creates the token and can trigger cancellation with .Cancel(); the running code checks token.IsCancellationRequested or lets an awaited method throw OperationCanceledException. Cancellation is cooperative — the operation must actively check the token to actually stop.

Note: Pass the same CancellationToken down through every awaited call so cancellation propagates properly.

Example: CancellationToken

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

class Program
{
    static async Task Main(string[] args)
    {
        using var cts = new CancellationTokenSource();
        cts.CancelAfter(50);

        try
        {
            await Task.Delay(1000, cts.Token);
            Console.WriteLine("Completed normally");
        }
        catch (OperationCanceledException)
        {
            Console.WriteLine("Operation was cancelled");
        }
    }
}