在visual studio express 2013中“拖放形成”计时器不起作用

Question

I have no idea why this code does not work.

The timer just seams to freeze everything. As far as I know, the timer is sent to a newly created thread. I've tried locking on tick, but no luck.

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public int CountUp = 0;
        public Form1()
        {
            InitializeComponent();
            label1.Text = "Click To Start Timer";
            timer1.Enabled = false;
            timer1.Stop();
            timer1.Interval = 1000;

        }

        private void button1_Click(object sender, EventArgs e)
        {

            bool Toggled = false;
            if (!Toggled)
            {
                timer1.Enabled = true;
                Toggled = true;
            }
            else
            {
                timer1.Enabled = false;
                Toggled = false;
                label1.Text = "Timer Stopped";
                CountUp = 0;
            }
            while(Toggled){
                label1.Text = "Timer1 Running";
            }
        }

        private void timer1_Tick(object sender, EventArgs e)
        {
            //lock (label2.Text) <- froze the program immediately
            //{
            //    CountUp++;
            //    string CurrentTime = CountUp.ToString();
            //    label2.Text = CurrentTime;
            //}
            CountUp++;
            string CurrentTime = CountUp.ToString();
            label2.Text = CurrentTime;
            //CurrentTime = timer1.ToString() = Garbage & freeze.
        }

    }
}

Any suggestions? It may be the key to solving this question .

Answer 1

The while(Toggled){ .. } code will freeze the interface and hang the program as it blocks the UI thread. However, the Forms.Timer , which relies on the UI event queue being processed, will never fire due to the blocking loop - as such, the flag variable will never be "reset".

While one of the threaded timers could be used, it would still result in an un-responsive UI. The solution is to design [WinForm] programs to react to events , such as when the timer starts and when it stops ¹ .

---

¹ There are actually no start/stop events per-se, but do the actions when the timer is started or stopped by the code. For example,

private void button1_Click(object sender, EventArgs e)
{
    if (!timer1.Enabled) {
        CountUp = 0;
        timer1.Enabled = true;
        label1.Text = "Timer1 Running";
    } else {
        timer1.Enabled = false;
        label1.Text = "Timer1 Stopped (Manual)";
    }
}

// Later on, when a tick occurs and the timer should end..
// The timer callback runs on the UI thread it was created on.
private void timer1_Tick(object sender, EventArgs e)
{
    CountUp++;
    if (CountUp > 10) {
        timer1.Enabled = false;
        label1.Text = "Timer1 Stopped (Time up)";
    }
}

There is no need to use lock at all because all of the code should be running on the UI thread.