C＃由于循环依赖而在未引用的项目中调用方法

Question

I have two class's controller and the CountDownTimer. The project with the controller references the project with the CountDownTimer class. I have methods(TickUpdate) in the CountDownTimer class which call methods in the controller class every time the timer counts down by aa second. But because of circular dependency i cannot reference controller project in the CountDownTimer project.

So my question, is the any way to call the TickUpdate method from the countdown class?

using SailTimerClassLibrary;

namespace SailTimerUIProject
{
    public class Controller : ApplicationContext
    {
    //Store a reference to the UI
    internal frmMain MainUI { get; set; }

    private int seconds = 30;
    CountDownTimer timer;

    public Controller()
    {

        MainUI = new frmMain(this);

        //We can do any necessary checks or changes to the MainUI here before it becomes visible
        MainUI.Show();
        timer = new CountDownTimer(seconds);
        TickUpdate(("" + seconds / 60).PadLeft(2, '0') + "m:" + ("" + seconds % 60).PadLeft(2, '0') + "s");
    }

    internal void TickUpdate(string mmss)
    {
        MainUI.lblTimer.Text = mmss;
    }

    internal void StartTimer()
    {
        timer.StartTimer();
    }
}
}



namespace SailTimerClassLibrary
{
public class CountDownTimer : ICountDownTimer
{
    private int seconds; // Time in seconds
    private int reSetValue; // Time in seconds
    public System.Windows.Forms.Timer timer1;

    public CountDownTimer(int seconds)
    {
        this.seconds = seconds;
        reSetValue = seconds;
        timer1 = new System.Windows.Forms.Timer();
        timer1.Tick += new EventHandler(timer1_Tick); // Add Handler(timer1_Tick)
        timer1.Interval = 1000; // 1 second
        //TickUpdate(("" + seconds / 60).PadLeft(2, '0') + "m:" + ("" + seconds % 60).PadLeft(2, '0') + "s");
    }

    public void timer1_Tick(object sender, EventArgs e)
    {
        seconds--; // Decrement seconds
        if (seconds == 0) // Stop Timer at 0
        {
            timer1.Stop(); // Stop timer
        }
        else
        {
            //TickUpdate(convertSecondToMMSS());

            if (seconds % 60 == 0 || seconds >= 1 && seconds <= 10)
            {
                //TickUpdate(seconds);
            }
        }
    }

    public void StartTimer()
    {
        timer1.Start(); // Start Timer
    }

    public string convertSecondToMMSS()
    {
        TimeSpan t = TimeSpan.FromSeconds(seconds);
        string str = string.Format("{0:D2}m:{1:D2}s", //{0:D2}h:{1:D2}m:{2:D2}s:{3:D3}ms
            t.Minutes,
            t.Seconds);

        return str;
    }

    public void StopTimer()
    {
        timer1.Stop();
    }

    public void ResetTimer()
    {
        timer1.Stop();
        seconds = reSetValue;
        //parent.TickUpdate(convertSecondToMMSS());
    }

    public void SetTimer(int seconds)
    {
        timer1.Stop();
        this.seconds = seconds;
        reSetValue = seconds;
        //parent.TickUpdate(convertSecondToMMSS());
    }
}
}

Answer 1

A few design issues here are hampering your ability.

The CountDownTimer should probably be in an ancillary project or class library that both of these projects reference. This avoids the whole circular dependency problem. But what about controllers?!
Well....

CountDownTimer should not know about controllers, or anything else for that matter! It should expose an event of some kind that the controllers can add a handler to, and the controllers can update themselves .