How to implement a software interrupt?

Question

I'm dealing with an C# Windows Forms application. I have some forms and all these forms are sensitive to the value of a global variable. [Static Member Of A Static Class]

I don't want to run a timer on every form and check this variable. I want these forms to be sensitive to the value of this variable and each form to perform its own routine.

What should I do? Is there a standard way to implement these types of algorithms?

Answer 1

It's a normal situation. Sometimes we need to use something like timers. (This is called Polling method). Sometimes we need Interrupts (This is called Event in the C# terminology).

So. As you said we have an static class:

internal static class StaticClass
{
    public delegate void SomethingHappendEventHandler(object sender, EventPayload e);

    public static event SomethingHappendEventHandler SomethingHappendEvent;

    public class EventPayload
    {
        public string Message { get; set; }
    }
    
    public static async Task BroadcastAnEvent(string message)
    {
        SomethingHappendEvent?.Invoke(null, new EventPayload()
        {
            Message = message
            // Extra info should be defined in payload class if you want to pass them.
        });
    }
}

and we have some Forms that wanna catch those Events. for every single form you should do this:

    public ChildForm()
    {
        InitializeComponent();

        StaticClass.SomethingHappendEvent += StaticClass_SomethingHappendEvent;
    }

    private void StaticClass_SomethingHappendEvent(object sender, StaticClass.EventPayload e)
    {
        MessageBox.Show(e.Message);
    }

You can call:

 StaticClass.BroadcastAnEvent("My message");

Wherever you want and all of these forms will catch this message and they are able to use it.