我有一个表格，我附上了一个计时器。我想在表单上显示stopwatch并每秒更新一些值到数据库。我使用windows.form计时器来完成它。但问题是它使我的应用程序非常慢并且stopwatch没有正确显示时间。更新需要3-4秒。
另外当我点击另一个按钮时，计时器也会中断。我需要stopwatch正确的工作，毫不拖延。我现在该怎么办？
代码如下：
public partial class Form2 : Form
{
Stopwatch sw = new Stopwatch();
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;
private TimeSpan timerSinceStartTime = 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(timer1_Tick);
label4.Text = UserName;
}
public static class LoginInfo
{
public static string UserID;
}
private void richTextBox2_TextChanged(object sender, EventArgs e)
{
}
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;
}
sw.Start();
SqlDataReader rd1;
SqlConnection Con = new SqlConnection("Data Source=69.162.83.242,1232;Initial Catalog=test1;Uid=test;pwd=1234@Test;MultipleActiveResultSets=true;Connect TimeOut=600;");
//SqlConnection Con = new SqlConnection("Data Source=ADMIN-PC\\YASH;Initial Catalog=test;Integrated Security=True; Connect TimeOut=600");
Con.Open();
rd1 = new SqlCommand("Select SName from ExpertChat where email ='" + label4.Text + "'", Con).ExecuteReader();
rd1.Read();
string str;
str = rd1["SName"].ToString();
rd1.Close();
string messageMask = "{0} @ {1} : {2}";
string message = string.Format(messageMask, str, DateTime.Now.ToShortTimeString(), richTextBox2.Text);
richTextBox1.AppendText(Environment.NewLine + message);
SqlCommand cmd, cmd1;
cmd = new SqlCommand("Update Chat set UserInitial=@message where ExpertName ='" + str + "'", Con);
cmd.Parameters.AddWithValue("@message" ,message);
cmd.ExecuteNonQuery();
cmd1 = new SqlCommand("Update Chat set Updated=1 where ExpertName ='" + str + "'", Con);
cmd1.ExecuteNonQuery();
Con.Close();
richTextBox2.Text = String.Empty;
richTextBox1.ScrollToCaret();
}
private void button3_Click(object sender, EventArgs e)
{
sw.Stop();
_timer.Stop();
_timerRunning = false;
// Reset the elapsed time TimeSpan objects
_totalElapsedTime = TimeSpan.Zero;
_currentElapsedTime = TimeSpan.Zero;
label3.Text = _totalElapsedTime.ToString();
MessageBox.Show(count.ToString());
SqlConnection Con = new SqlConnection("Data Source=69.162.83.242,1232;Initial Catalog=test1;Uid=test;pwd=1234@Test;MultipleActiveResultSets=true;Connect TimeOut=600;");
//SqlConnection Con = new SqlConnection("Data Source=ADMIN-PC\\YASH;Initial Catalog=test;Integrated Security=True; Connect TimeOut=600");
Con.Open();
SqlDataReader rd1;
rd1 = new SqlCommand("Select SName from ExpertChat where email ='" + label4.Text + "'", Con).ExecuteReader();
rd1.Read();
string str;
str = rd1["SName"].ToString();
rd1.Close();
SqlDataReader cmd1;
cmd1 = new SqlCommand("Update Expertchat Set Booked=0 where email='" + label4.Text + "'", Con).ExecuteReader();
cmd1.Close();
SqlDataReader cmd2;
cmd2 = new SqlCommand("Update chat set EndChat=1,ChatTime=" + count + " where ExpertName='" + str + "'", Con).ExecuteReader();
cmd2.Close();
count = 0;
Con.Close();
this.Close();
}
private void pictureBox1_Click(object sender, EventArgs e)
{
}
private void Form2_Load(object sender, EventArgs e)
{
}
private void richTextBox1_TextChanged(object sender, EventArgs e)
{
}
private void richTextBox1_TextChanged_1(object sender, EventArgs e)
{
}
private void linkLabel2_LinkClicked(object sender, LinkLabelLinkClickedEventArgs e)
{
SqlConnection Con = new SqlConnection("Data Source=69.162.83.242,1232;Initial Catalog=test1;Uid=test;pwd=1234@Test;MultipleActiveResultSets=true;Connect TimeOut=600;");
//SqlConnection Con = new SqlConnection("Data Source=ADMIN-PC\\YASH;Initial Catalog=test;Integrated Security=True; Connect TimeOut=600");
Con.Open();
SqlDataReader rd1;
rd1 = new SqlCommand("Select SName from ExpertChat where email ='" + label4.Text + "'", Con).ExecuteReader();
rd1.Read();
string str;
str = rd1["SName"].ToString();
rd1.Close();
SqlDataReader rd2 = new SqlCommand("Select top 1 UserName from Chat where ExpertName ='" + str + "'", Con).ExecuteReader();
rd2.Read();
string str1;
str1 = rd2["UserName"].ToString();
LoginInfo.UserID = str1;
Con.Close();
ClientDetails frm = new ClientDetails(LoginInfo.UserID);
frm.Show();
}
private void label3_Click(object sender, EventArgs e)
{
}
private void timer1_Tick(object sender, EventArgs e)
{
count = count + 1;
timerSinceStartTime = new TimeSpan(timerSinceStartTime.Hours, timerSinceStartTime.Minutes, timerSinceStartTime.Seconds + 1);
// The current elapsed time is the time since the start button was
// clicked, plus the total time elapsed since the last reset
_currentElapsedTime = timerSinceStartTime + _totalElapsedTime;
// These are just two Label controls which display the current
// elapsed time and total elapsed time
SqlDataReader rd1;
SqlConnection Con = new SqlConnection("Data Source=69.162.83.242,1232;Initial Catalog=test1;Uid=test;pwd=1234@Test;MultipleActiveResultSets=true;Connect TimeOut=600;");
//SqlConnection Con = new SqlConnection("Data Source=ADMIN-PC\\YASH;Initial Catalog=test;Integrated Security=True; Connect TimeOut=600");
Con.Open();
rd1 = new SqlCommand("Select SName from ExpertChat where email ='" + label4.Text + "'", Con).ExecuteReader();
rd1.Read();
string str;
str = rd1["SName"].ToString();
rd1.Close();
SqlDataReader rd;
rd = new SqlCommand("Select top 1 Data,Updated1 from Chat where ExpertName ='" + str + "' order by id desc", Con).ExecuteReader();
rd.Read();
string str5;
int i;
str5 = rd["Data"].ToString();
i = Int32.Parse(rd["Updated1"].ToString());
rd.Close();
if (i == 1)
{
richTextBox1.AppendText(Environment.NewLine + str5);
SqlCommand cmd1 = new SqlCommand("Update Chat set Updated1=0 where ExpertName ='" + str + "'", Con);
cmd1.ExecuteNonQuery();
}
label3.Text = timerSinceStartTime.ToString();
// If we're running on the UI thread, we'll get here, and can safely update
// the label's text.
richTextBox1.ScrollToCaret();
}
private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
}
private void button2_Click(object sender, EventArgs e)
{
}
private void button4_Click(object sender, EventArgs e)
{
}
}
}
答案 0 :(得分：3)
问题是在UI线程中执行了长时间运行的数据库操作。这意味着由于UI线程忙，计时器事件无法触发。解决方案是将长时间运行的操作放在远离UI的不同线程上。
答案 1 :(得分：1)
您的数据库代码会变慢。由于您是在UI线程中执行此操作，因此它会阻止您的应用程序。 为了达到预期的目标，你必须做（至少）两件事：
将数据库代码移至background worker，task或另一个 线程。
优化代码。这个查询不是那么慢。