尝试以C＃中的形式更改计时器的输出

Question

I need to make a form in C# have a timer and have a label that will have be the display of the timer. The label will need to be a generic label at first saying it is a counter, but when the timer starts it needs to display the count. Currently I have the display as a number up down but, it needs to be the control that can tweak the count, which it does. It just can't be the sole counter.

Here is my assignment:

Create a Windows Application. In the main form, create a label named “lTickCount”. Create a timer named “tPeriodic”, and a numerical control of your own choosing. Each time the timer “ticks” increment an integer, display the integer value as a string in lTickCount. Use the numerical control to change the update rate of the timer interactively.

I think I have done everything correctly except for the bold part. To finish I tried to make a string in both the label and the counter. I know I shouldn't have in both, I just wanted to show you the two things I've tried to help get better feedback:

namespace WindowsFormsApplication3
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            this.Text = "AAAAAAAA AAAAAAAA ########";
        }

        private void checkBox1_CheckedChanged(object sender, EventArgs e)
        {
            if (checkBox1.Checked)
            {
                TickCounter.Text = "The timer has started";
                tPeriodic.Enabled = true;
            }
            else
            {
                TickCounter.Text = "The timer has ended";
                tPeriodic.Enabled = false;
            }

        }

        private void TickCounter_ValueChanged(object sender, EventArgs e)
        {
            TickCounter.Text = TickCounter.Value.ToString();
        }

        private void tPeriodic_Tick(object sender, EventArgs e)
        {
            TickCounter.Value += 1;
        }

        private void label1_Click(object sender, EventArgs e)
        {
            TickCounter.Text = TickCounter.Value.ToString();
        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }
    }
}

Can someone help me figure out what I'm doing wrong and point me in the right way?

Answer 1

If you are going to try to add to a string (A label value) you need to convert it to an Integer first.

A couple ways to do this:

TextCount.Text = (Convert.ToInt32(TextCount.Text) + 1).ToString();

is one way, of course you could still use your += or any other math syntax for basic addition of +1.

You can also use tryParse, and in fact this should probably be used to verify you have an integer in the first place:

   int count;
   if (int.TryParse(TextCount.Text, out count))
        {
            count++;
            TextCount.Text = count.ToString();
        }

Answer 2

int count;
int tmrInterval = 1000; //1 sec
private void tPeriodic_Tick(object sender, EventArgs e)
{
    count++;
    lTickCount.Text = count.ToString();
}

private void TickCounter_ValueChanged(object sender, EventArgs e)
{
    if (TickCounter.Value == 0)
    {
        return; // or stop the timer
    }
    tPeriodic.Interval = TickCounter.Value * tmrInterval;
}

tPeriodic.Interval is the time till next tick in milliseconds. You are updating the timer interval according to tmrInterval and the value of the numeric control. You can change the interval or the formula i wrote to your own.

valter

Answer 3

Ok I found that:

tPeriodic.Interval = 1000 / Convert.ToInt32(TickCounter.Value * TickCounter.Value);

seemed to work in the numericupdown class.

Thanks for the help.