如何取消正在使用 Task.Run() 运行的现有任务？

Question

The below mentioned UpdateMethod Can be called from various User actions like button UpdateSW1, UpdateSW2, UpdateSW3.

If the User clicks on button UpdateSW1, it pauses the task for 10 seconds, waitTime is 2 here. Now while this click is done, User Can click on UpdateSW2 also, when that happens, I want to cancel the ongoing delay or other operation of the Task as a result of first click (UpdateSW1) and start the operations for UpdateSW2.

private void UpdateMethod(int waitTime, int actionNo)
    {
        Task.Run(async () =>
        {
            while (waitTime != 0)
            {
                waitTime--;
                await Task.Delay(5000);
            }
            // DO other stuff ...

            if (actionNO == 1)
            {
                //ops for UpdateSW1
            }
            else
            {
                //ops for UpdateSW2.
            }
        });
    }

Update1:

After some trial I came up with following code, now this works fine to some extent, but still needs improvement. What happens is if the user clicks on button UpdateSW1 and UpdateSW2 in a sequence and then i Click on the cancel button, it cancels one of the task (which is running as a result of UpdateSW1 click ) but does not cancel the other (one which is running as a result of click on updteSW2) I wish to cancel both the tasks. How to achieve this.

Modified method:

private CancellationTokenSource cts; // declared as class variable. 

private void UpdateMethod(int waitTime, int actionNo)
    {
        cts = new CancellationTokenSource();
        CancellationToken token1 = cts.Token;
        try
        {
            Task.Run(async () =>
            {
                while (waitTime != 0)
                {
                    waitTime--;
                    await Task.Run(() => Task.Delay(5000, token1), token1);
                    token1.ThrowIfCancellationRequested();
                }
                // DO other stuff ...

                if (actionNO == 1)
                {
                    //ops for UpdateSW1
                }
                else
                {
                    //ops for UpdateSW2.
                }
            }, token1);
        }
        catch (OperationCanceledException e)
        {
            // update DB log
        }
    }

Answer 1

This entire wait loop

            while (waitTime != 0)
            {
                waitTime--;
                await Task.Run(() => Task.Delay(5000, token1), token1);
                token1.ThrowIfCancellationRequested();
            }

can be simplified to

await Task.Delay(waitTime, token1);

When the token is signaled, the delay will end. No need to do that in a roundabout manner.