为什么我的eventandler从来没有停止调用，即使我停止了定时器?我的代码有问题吗?请帮助!
我已经包含了我的整个代码里面，如果你们能做我一些帮助请:)
private void Form1_Load(object sender, EventArgs e)
{
//Start system
axInRFIDCtrl1.SelectReaderFeig();
axInRFIDCtrl1.FEInit();
short sResult = axInRFIDCtrl1.FEOpen();
//MessageBox.Show(sResult.ToString());
//Start timer1
System.Windows.Forms.Timer timer1 = new System.Windows.Forms.Timer();
timer1.Interval = 1000;
timer1.Tick += new EventHandler(timer1_Tick);
timer1.Enabled = true;
timer1.Start();
Console.ReadLine();
}
public void timer1_Tick(object sender, EventArgs e)
{
//Get ID
string strTagIds = string.Empty;
int iState = 0;
axInRFIDCtrl1.FESelect(ref strTagIds, ref iState);
string[] strTagID = strTagIds.Split(new char[] { '|' });
string strTag = strTagID[0];
textBox1.Text = strTag;
//Connection to datebase
string c1 = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\Project.mdb";
OleDbConnection con = new OleDbConnection(c1);
//Bind button
string txt = textBox1.Text;
string strOleDbConnectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\Project.mdb";
string strSqlStatement = string.Empty;
strSqlStatement = "SELECT * FROM jiahe WHERE [Tag ID] = '" + txt + "'";
OleDbConnection objConnection = new OleDbConnection(strOleDbConnectionString);
OleDbDataAdapter objAdapter = new OleDbDataAdapter(strSqlStatement, objConnection);
DataSet ds = new DataSet();
objAdapter.Fill(ds);
DataTable dt = ds.Tables[0];
dataGridView1.DataSource = dt.DefaultView;
if (dt.Rows.Count == 1)
{
string strLine = string.Empty;
string strUser = string.Empty;
foreach (DataRow dr in dt.Rows)
{
string strTags = dr["Tag ID"].ToString();
strUser = dr["User"].ToString();
string strAge = dr["Age"].ToString();
string strPhoneNumber = dr["Phone Number"].ToString();
// prepare command string
string selectString = @"SELECT Status FROM jiahe where [Tag ID] = '" + textBox1.Text + "'";
// 1. Instantiate a new command with command text only
OleDbCommand cmd = new OleDbCommand(selectString, objConnection);
// 2. Set the Connection property
cmd.Connection.Open();
// 3. Call ExecuteScalar to send command
string str = cmd.ExecuteScalar().ToString();
cmd.Connection.Close();
foreach (DataRow datarow in dt.Rows)
{
//string strName = string.Empty;
strName = datarow["User"].ToString();
if (str.Length == 2 || str.Length == 0)
{
// prepare command string
string updateString = @"update jiahe set Status = 'OUT' where [Tag ID] = '" + textBox1.Text + "'";
// 1. Instantiate a new command with command text only
OleDbCommand cmd1 = new OleDbCommand(updateString, objConnection);
// 2. Set the Connection property
cmd1.Connection.Open();
// 3. Call ExecuteNonQuery to send command
str = cmd1.ExecuteNonQuery().ToString();
cmd1.Connection.Close();
//write text file to outgoing spool
//TextWriter tw = new StreamWriter(@"C:cygwinvarspoolsmsoutgoingsms.txt");
TextWriter tw = new StreamWriter(@"C:\Test.txt");
{
tw.WriteLine("To: 6592786618n");
tw.WriteLine("n");
tw.WriteLine("n" + strName + @" has just left at " + DateTime.Now);
tw.Close();
}
MessageBox.Show(strName + " has left the house.");
//Start timer2
System.Windows.Forms.Timer timer2 = new System.Windows.Forms.Timer();
timer2.Interval = 1000 * 60 * 30; //30 mins interval
timer2.Tick += new EventHandler(timer2_Tick);
timer2.Enabled = true;
timer2.Start();
//Log to listbox
// Set the selection mode to multiple and extended.
listBox1.SelectionMode = SelectionMode.MultiExtended;
listBox1.BeginUpdate();
listBox1.Items.Add(DateTime.Now + " - " + strName + " > OUT");
listBox1.EndUpdate();
//Log event to log file
string cs = "Minder+Finder Event Log";
EventLog elog = new EventLog();
if (!EventLog.SourceExists(cs))
{
EventLog.CreateEventSource(cs, cs);
}
elog.Source = cs;
elog.EnableRaisingEvents = true;
elog.WriteEntry(DateTime.Now + " - " + strName + " > OUT");
}
else
{
// prepare command string
string updateString = @"update jiahe set Status = 'IN' where [Tag ID] = '" + textBox1.Text + "'";
// 1. Instantiate a new command with command text only
OleDbCommand cmd1 = new OleDbCommand(updateString, objConnection);
// 2. Set the Connection property
cmd1.Connection.Open();
// 3. Call ExecuteNonQuery to send command
str = cmd1.ExecuteNonQuery().ToString();
cmd1.Connection.Close();
//write text to outgoing spool
TextWriter tw = new StreamWriter(@"C:\Test.txt");
//using (TextWriter tw = File.CreateText("C:cygwinvarspoolsmsoutgoingTest.txt"));
{
tw.WriteLine("To: 6592786618n");
tw.WriteLine("n");
tw.WriteLine("n" + strName + @" has just returned home at " + DateTime.Now);
tw.Close();
}
MessageBox.Show(strName + " has returned home.");
//Stop timer2
timer2.Tick -= timer2_Tick;
timer2.Enabled = false;
timer2.Stop();
//Log to listbox
// Set the selection mode to multiple and extended.
listBox1.SelectionMode = SelectionMode.MultiExtended;
listBox1.BeginUpdate();
listBox1.Items.Add(DateTime.Now + " - " + strName + " > IN");
listBox1.EndUpdate();
//Log event to log file
string cs = "Minder+Finder Event Log";
EventLog elog = new EventLog();
if (!EventLog.SourceExists(cs))
{
EventLog.CreateEventSource(cs, cs);
}
elog.Source = cs;
elog.EnableRaisingEvents = true;
elog.WriteEntry(DateTime.Now + " - " + strName + " > IN");
}
}
}
}
else
{
timer1.Enabled = false;
}
}
private void button1_Click(object sender, EventArgs e)
{
Form2 form2 = new Form2();
form2.ShowDialog();
}
private void button2_Click(object sender, EventArgs e)
{
Form3 form3 = new Form3();
form3.ShowDialog();
}
public void timer2_Tick(object sender, EventArgs e)
{
MessageBox.Show(strName + " has left");
//write text file to outgoing spool
//TextWriter tw = new StreamWriter(@"C:cygwinvarspoolsmsoutgoingsms.txt");
TextWriter tw = new StreamWriter(@"C:\Test1.txt");
{
tw.WriteLine("To: 6592786618n");
tw.WriteLine("n");
tw.WriteLine("n" + strName + @" has just left at " + DateTime.Now);
tw.Close();
}
}
如果timer2是一个实例变量，那么问题是您正在创建一个也称为timer2的局部变量并启动它。然后停止成员变量timer2，而不是局部作用域timer2。局部作用域timer2将一直触发，直到垃圾收集器处理它。
我很确定timer2是一个实例变量，否则对它的其他引用将无法编译。还需要注意的是，由于是在循环中创建timer2，因此可能会创建一船的timer2，并且它们都愉快地继续工作，直到垃圾收集器将它们从痛苦中解脱出来。
编辑:这是一个在表单中使用的相当简单的例子。
http://www.java2s.com/Code/CSharp/GUI-Windows-Form/GUIandtimer.htm如果您只是将计时器组件放到表单设计中，那么初始化将在InitializeComponents方法中为您编写，如下例所示。除了这个，我也帮不上什么忙了。我认为你使用计时器的方式存在一些结构性问题。所有的开始和停止，特别是在for循环中的timer2，似乎会给您带来很多麻烦和头痛。
如果您停止定时器(通过调用Stop()或通过设置Enabled = false)，那么它将不会再次触发。我从来没有看到过停止计时器调用事件处理程序的情况。如果事件处理程序在禁用计时器后仍然被调用，那么要么是其他代码正在调用它，要么是某些东西正在重新启用计时器。
还请注意，如果事件处理程序当前正在执行，停止计时器将不会中止事件。它也不会阻止任何挂起的事件。虽然这应该不是System.Windows.Forms.Timer的问题，因为它的事件处理程序总是在GUI线程上执行。
如果我是你，我会非常仔细地检查代码，查看所有启用或禁用计时器的地方。我怀疑你会发现你的代码中有什么东西重新启用定时器。
看到你发布的代码后编辑:
可能的问题是，在您的计时器事件处理程序中，您有以下内容:
System.Windows.Forms.Timer timer2 = new System.Windows.Forms.Timer();
// code that initializes and enables timer
创建了一个局部timer2变量，它将不同于窗体作用域中的timer2(我假设，因为您暗示代码编译，并且您在单独的作用域中引用timer2)。您最终创建了一个新的计时器，但是禁用计时器的代码引用了表单范围timer2。所以发生的事情是，你创建了很多不同的计时器，它们中的每一个最终调用相同的事件处理程序。
我希望你在事件处理程序中调用MessageBox.Show只是为了调试目的。你不希望把它们留在那里，因为它们会阻塞UI线程，并且会阻止额外的计时器滴答，直到它们被解除。
你的停止代码最好是:
//Stop timer2
timer2.Stop();
timer2.Tick -= timer2_Tick;
这段代码从未触发计时器，因为它在时间结束之前(通过三种不同的方式)被阻止了。