C# alert when deadline date is approaching

Question

Ok so I have an application that stores records and does various other functions, I would like to be able to implement a way of creating some sort of alert system where by when a deadline date (stored with any record) is approaching it will tell me/user. Not sure if this is possible but any advice or suggestions would be great thanks.

Answer 1

Using System.DateTime you should be able to access the current date of the machine like this

DateTime today = DateTime.Today;

You could compare this with the stored time in your records at a regular intervall (start of the application maybe?) to check if the deadline is approaching.

Answer 2

You could fire up a separate task to iterate through bunch of records in nob-blocking manner forever and check if you need to take some action. Here's a working WPF example for you to open up the concept. I think you can figure out how to apply it to your specific needs.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using System.Windows;

namespace WpfApplication
{
    public partial class MainWindow : Window
    {
        private readonly List<MyEvent> _myEvents;

        public MainWindow()
        {
            InitializeComponent();
            DataContext = this;

            // Add some dummy events occuring on specific time
            _myEvents = new List<MyEvent>()
                {
                    new MyEvent("My event A", DateTime.Now.AddSeconds(5)),
                    new MyEvent("My event B", DateTime.Now.AddSeconds(10)),
                    new MyEvent("My event C", DateTime.Now.AddSeconds(20))
                };

            // Fire up the event iterator
            Task.Factory.StartNew(() =>
                {
                    while (true)
                    {
                        // Report events' status
                        DateTime now = DateTime.Now;

                        foreach (var myEvent in _myEvents.Where(e => e.Time <= now))
                            System.Diagnostics.Debug.WriteLine(string.Format("Event '{0}' already held", myEvent.Name));

                        foreach (var myEvent in _myEvents.Where(e => e.Time > now))
                        {
                            string notification = "Event '{0}' at '{1}' starting in {2} seconds";
                            TimeSpan timeSpan = myEvent.Time - now;
                            notification = string.Format(notification, myEvent.Name, myEvent.Time, (int)timeSpan.TotalSeconds);
                            System.Diagnostics.Debug.WriteLine(notification);
                        }
                        System.Diagnostics.Debug.WriteLine(new string('-', 15));

                        // Wait for a while before next iteration
                        Thread.Sleep(3000);
                    }
                });
        }
    }

    // Dummy
    public class MyEvent
    {
        public MyEvent()
        {}

        public MyEvent(string name, DateTime time)
        {
            Name = name;
            Time = time;
        }

        public string Name { get; set; }

        public DateTime Time { get; set; }
    }
}

Output from this example would be something like:

Event 'My event A' at '6.3.2014 18:34:02' starting in 4 seconds
Event 'My event B' at '6.3.2014 18:34:07' starting in 9 seconds
Event 'My event C' at '6.3.2014 18:34:17' starting in 19 seconds
---------------
Event 'My event A' at '6.3.2014 18:34:02' starting in 1 seconds
Event 'My event B' at '6.3.2014 18:34:07' starting in 6 seconds
Event 'My event C' at '6.3.2014 18:34:17' starting in 16 seconds
---------------
Event 'My event A' already held
Event 'My event B' at '6.3.2014 18:34:07' starting in 3 seconds
Event 'My event C' at '6.3.2014 18:34:17' starting in 13 seconds
---------------
Event 'My event A' already held
Event 'My event B' at '6.3.2014 18:34:07' starting in 0 seconds
Event 'My event C' at '6.3.2014 18:34:17' starting in 10 seconds
---------------

Happy coding!