示例
/// <summary>
///取消注册具有给定名称的单个后台任务
/// </summary>
/// <param name="taskName">task name</param>
/// <param name="cancelTask">true if task should be cancelled, false if allowed to finish</param>
public void UnregisterTask(string taskName, bool cancelTask) =>
BackgroundTaskRegistration.AllTasks.First(x => x.Value.Name.Equals(taskName)).Value?.Unregister(cancelTask);
/// <summary>
///取消注册一组活动的后台任务，该任务名称包含给定的字符串
/// </summary>
/// <param name="taskNamePart">part of the task name</param>
/// <param name="cancelTask">true if tasks should be cancelled, false if allowed to finish</param>
public void UnregisterTasks(string taskNamePart, bool cancelTask)
{
foreach (var task in BackgroundTaskRegistration.AllTasks.Where(x => x.Value.Name.Contains(taskNamePart)))
task.Value.Unregister(cancelTask);
}
