Request task cancellation extension method

Request task cancellation extension method

An extension method to request the cancellation of a CancellationTokenSource.

A common pattern I came across when writing async methods that could be cancelled with a CancellationTokenSource was:

if (this.cancellationTokenSource != null && !this.cancellationTokenSource.IsCancellationRequested)
{
    this.cancellationTokenSource.Cancel();
}

Instead of repeating the code across the project I wanted to encapsulate this into a method, extending the CancellationTokenSource class. So I refactored the code into an extension method.

public static class CancellationTokenSourceExtensions
{
    public static void CancelIfCancellable(this CancellationTokenSource ctx)
    {
        if (ctx != null && !ctx.IsCancellationRequested)
        {
            ctx.Cancel();
        }
    }
}

This can be called like so.

this.cancellationTokenSource.CancelIfCancellable();

Now our methods are much cleaner and simpler. Win!