一次注册后台任务

Question

I have a background task that registers when the user enters the app using this code:

            await BackgroundExecutionManager.RequestAccessAsync();

            BackgroundTaskBuilder taskBuilder = new BackgroundTaskBuilder { Name = "First Task", TaskEntryPoint = "myTask.FirstTask" };
            taskBuilder.SetTrigger(new TimeTrigger(15, false));
            BackgroundTaskRegistration myFirstTask = taskBuilder.Register();

It works fine, and the task registers, however it continues to register again every time the app opens. Is there any way, using if , for example, to detect if a task is registered, therefore only registering a task once and not repeating the same process over and over again?

This problem was discovered by clicking on 'lifecycle events', which revealed about 15 instances of 'First Task', if that helps.

Answer 1

Use the BackgroundTaskRegistration.AllTasks collection to check whether your task has already been registered:

if (BackgroundTaskRegistration.AllTasks.Values.Any(b => b.Name == "First Task"))
{
    // Already registered
}

Answer 2

You can use a isolated storage setting for this. When the app starts look for an isolated storage setting if the setting is not there register the background task and create the setting.