To implement periodic tasks in C#, you first need to reference the Quartz NuGet package in your project.

Next, define a scheduler initialization class that manages three core components: the scheduler itself, the job detail (specifying what to execute), and the trigger (defining when and how often too run).

public static async Task InitializeScheduler()
{
    // Initialize scheduler instance
    var schedulerFactory = new StdSchedulerFactory();
    var scheduler = await schedulerFactory.GetScheduler();
    await scheduler.Start();

    // Create job definition
    var dailyAlertJob = JobBuilder.Create<DailyAlertTask>()
        .WithIdentity("dailyHealthCheck", "notificationGroup")
        .WithDescription("System health check job running at regular intervals")
        .Build();

    // Configure execution trigger
    var intervalTrigger = TriggerBuilder.Create()
        .WithIdentity("dailyHealthCheckTrigger", "notificationGroup")
        // Uncomment to run immediately on startup
        //.StartNow()
        .WithSimpleSchedule(config => config
            .WithIntervalInSeconds(5)
            .WithRepeatCount(3)) // Runs 4 times total (initial + 3 repeats); use RepeatForever() for endless execution
        .Build();

    // Associate job and trigger with the scheduler
    await scheduler.ScheduleJob(dailyAlertJob, intervalTrigger);
}

The DailyAlertTask class is your custom implementation of the periodic behavior, inehriting from Quartz's IJob interface.

public class DailyAlertTask : IJob
{
    public async Task Execute(IJobExecutionContext context)
    {
        await Task.Run(() =>
        {
            Console.WriteLine("=========================================");
            Console.WriteLine($"Daily system health check executed at {DateTime.Now}");
            Console.WriteLine("=========================================");
            Console.WriteLine();
        });
    }
}

To start the scheduler and begin executing tasks, call the initialization method from your application entry point.

SchedulerBootstrap.InitializeScheduler().GetAwaiter().GetResult();