c# - 如何在不使用计时器的情况下以 Windows 形式显示秒表

Question

我是这个领域的新人。我在我的窗口窗体中使用一个定时器，它以固定的时间间隔从数据库中获取数据。现在我希望我的计时器重新发送相同的邮件，但我需要在屏幕上显示秒表每秒运行一次。有什么办法吗？代码在这里.....

public partial class Form2 : Form
{
    private Timer _timer;
    int count = 0;
    // The last time the timer was started
    private DateTime _startTime = DateTime.MinValue;

    // Time between now and when the timer was started last
    private TimeSpan _currentElapsedTime = TimeSpan.Zero;

    // Time between now and the first time timer was started after a reset
    private TimeSpan _totalElapsedTime = TimeSpan.Zero;

    // Whether or not the timer is currently running
    private bool _timerRunning = false;
    public Form2(String UserName)
    {
        InitializeComponent();
        _timer = new Timer();
        _timer.Interval = 1000;
        _timer.Tick += new EventHandler(timer_Tick);
        label4.Text = UserName; 

    }


    private void richTextBox2_TextChanged(object sender, EventArgs e)
    {

    }


    private void timer_Tick(object sender, EventArgs e)
    {

        count = count + 1;
        var timeSinceStartTime = DateTime.Now - _startTime;
        timeSinceStartTime = new TimeSpan(timeSinceStartTime.Hours,
                                          timeSinceStartTime.Minutes,
                                          timeSinceStartTime.Seconds);

        // The current elapsed time is the time since the start button was
        // clicked, plus the total time elapsed since the last reset
        _currentElapsedTime = timeSinceStartTime + _totalElapsedTime;

        // These are just two Label controls which display the current 
        // elapsed time and total elapsed time

        label3.Text = timeSinceStartTime.ToString();
        String str1, str2;
        SqlDataReader rd1, rd2;
        SqlConnection Con = new SqlConnection("Data Source=216.218.224.238;Database=chatapp;Uid=chatappuser;pwd=1234@ChatAppUser;MultipleActiveResultSets=true;");
        // SqlConnection Con = new SqlConnection("Data Source=.\\SQLEXPRESS;Initial Catalog=Test;User ID=;Password=;Connection Timeout=600");
        Con.Open();

        rd1 = new SqlCommand("select top 1 Chat from chat where  where email ='" + label4.Text + "'order by id Desc", Con).ExecuteReader();
        rd1.Read();
        str1 = rd1["Chat"].ToString();
        rd1.Close();
        rd2 = new SqlCommand("select top 1 UserInitial from chat where email ='" + label4.Text + "' order by id Desc", Con).ExecuteReader();
        rd2.Read();
        str2 = rd2["UserInitial"].ToString();
        rd2.Close();
        if (str1 != str2)
        {
            SqlDataReader rd3, rd4;
            rd3 = new SqlCommand("select top 1 UserInitial from chat  where email ='" + label4.Text + "'order by id desc", Con).ExecuteReader();

            richTextBox1.Text = richTextBox1.Text + " <br /> " + rd3.Read();
            rd3.Close();
            rd4 = new SqlCommand("Update top 1 chat set Chat = UserInitial  where email ='" + label4.Text + "'order by id desc", Con).ExecuteReader();
            rd4.Read();
            rd4.Close();
            Con.Close();
        }

    }

    private void button1_Click(object sender, EventArgs e)
    {

        if (!_timerRunning)
        {
            // Set the start time to Now
            _startTime = DateTime.Now;

            // Store the total elapsed time so far
            _totalElapsedTime = _currentElapsedTime;

            _timer.Start();
            _timerRunning = true;
        }
        else // If the timer is already running
        {
            _timer.Stop();
            _timerRunning = false;
        }
        SqlDataReader rd5;
        SqlConnection Con = new SqlConnection("Data Source=216.218.224.238;Database=chatapp;Uid=chatappuser;pwd=1234@ChatAppUser;MultipleActiveResultSets=true;");
        // SqlConnection Con = new SqlConnection("Data Source=.\\SQLEXPRESS;Initial Catalog=Test;User ID=;Password=;Connection Timeout=600");
        Con.Open();
        richTextBox1.Text = richTextBox1.Text + "<br />Me:" + richTextBox2.Text;
        rd5 = new SqlCommand("Update chat set UserInitial ='" + richTextBox2.Text + "' order by id Desc where email ='" + label4.Text + "'", Con).ExecuteReader();
        rd5.Read();
        rd5.Close();
        Con.Close();
    }


    private void button3_Click(object sender, EventArgs e)
    {
        _timer.Stop();
        _timerRunning = false;

        // Reset the elapsed time TimeSpan objects
        _totalElapsedTime = TimeSpan.Zero;
        _currentElapsedTime = TimeSpan.Zero;
        label3.Text = _totalElapsedTime.ToString();  
        MessageBox.Show(count.ToString());
        count = 0;
    }

提前致谢......

Answer 1

您可以使用 StopWatch获取时间量的类 Elapsed

来自 MSDN:

Provides a set of methods and properties that you can use to accurately measure elapsed time.

第 1 步:创建一个 StopWatch 变量作为类级变量。

第 2 步:调用 Start() 方法，无论何时您想要开始计数。

第 3 步:对于每个 timer_tick 事件，您可以使用 stopwatch.Elapsed.Seconds 计算经过的总秒数。

试试这个:

Stopwatch watch = new Stopwatch();
watch.Start();
private void timer_Tick(object sender, EventArgs e)
{
  label1.Text = watch.Elapsed.Seconds.ToString();
}