我想在我的WPF应用程序中处理发生的System.Timers.Timer elapsed异常（在我的DLL库中）。但我做不到。它抛出我的DLL库，应用程序将崩溃...有人知道我该如何解决问题吗？
这是我的代码：
public partial class MainWindow : Window
{
MyClass _myClassInstance = null;
public MainWindow()
{
InitializeComponent();
try
{
_myClassInstance = new MyClass();
}
catch(Exception ex)
{
//Here i would like to receive the exception
//But it never goes in there
MessageBox.Show(ex.Message);
}
}
}
public class MyClass
{
private System.Timers.Timer _timer = null;
public MyClass()
{
_timer = new Timer();
_timer.Interval = 2000; //2 Seconds
_timer.Elapsed += new ElapsedEventHandler(_timer_Elapsed);
_timer.Start();
ConnectTo();
}
void _timer_Elapsed(object sender, ElapsedEventArgs e)
{
//If timer is elapsed I have to raise an exception
throw new Exception("It's taking longer than expected. Progress cancelled!");
}
private void ConnectTo()
{
//Just an example implementation
//Do something!!
//Connect to SerialPort and wait for correct response
//If connected than
_timer.Stop();
}
}
异常在另一个线程上引发（根据您对 Timing.Timer 的选择）。
在 1 个程序集中尝试这个：你也无法抓住它。它在 DLL 中并不重要。
您只能通过重新思考问题并选择另一种解决方案来解决这个问题。
异常发生在事件内部。这是在另一个线程上运行的，因此它永远不会返回到原始线程。
以不同的方式执行此操作的两种可能性。
- 您的串行端口com库具有某种超时功能（也许），只需使用它即可。
-
在单独的胎面上检查串行端口。如果你的时间用完了，那就杀死那个线程。
public class MyClass { private System.Timers.Timer _timer = null; private Thread t; public MyClass() { _timer = new Timer(); _timer.Interval = 2000; //2 Seconds _timer.Elapsed += new ElapsedEventHandler(_timer_Elapsed); _timer.Start(); t = new Thread(new ThreadStart(ConnectTo)); t.Start(); t.Join(); } void _timer_Elapsed(object sender, ElapsedEventArgs e) { //If timer is elapsed I have to raise an exception if (t != null) t.Abort(); } private void ConnectTo() { //Just an example implementation //Do something!! //Connect to SerialPort and wait for correct response //If connected than _timer.Stop(); } }
作为另一种方法，您可以改用事件来代替事件，而不是尝试使用异常来控制您的应用程序流。
public partial class MainWindow : Window
{
MyClass _myClassInstance = null;
public MainWindow()
{
InitializeComponent();
_myClassInstance = new MyClass();
_myClassInstance.TimedOut += delegate (object sender, EventArgs e) {
((MyClass)sender).CancelConnect();
MessageBox.Show("Timeout!");
};
_myClassInstance.ConnectTo();
}
}
...
public class MyClass
{
Timer _timer = new Timer();
public event EventHandler TimedOut;
void _timer_Elapsed(object sender, ElapsedEventArgs e)
{
OnTimedOut();
}
private void OnTimedOut()
{
var handler = TimedOut;
if (handler != null)
{
handler(this, EventArgs.Empty);
}
}
public void ConnectTo(int timeout = 2000)
{
CancelConnect();
_timer.Interval = timeout; // pass timeout in so it's flexible
_timer.Elapsed += new ElapsedEventHandler(_timer_Elapsed);
_timer.Start();
// do connect stuff...
_timer.Stop();
}
public void CancelConnect()
{
_timer.Stop();
// cancel connect stuff...
}
}
我认为您的构造函数中有太多的事情要做MyClass所以我将其移动到您直接从MainWindow调用的ConnectTo中。
不起作用：
MessageBox.Show（e.Message）; doen's throw
public class MyClass
{
private System.Timers.Timer _timer = null;
private Thread t;
public MyClass()
{
try
{
_timer = new System.Timers.Timer();
_timer.Interval = 5000; //2 Seconds
_timer.Elapsed += new ElapsedEventHandler(_timer_Elapsed);
_timer.Start();
t = new Thread(new ThreadStart(ConnectTo));
t.Start();
t.Join();
}
catch (Exception e)
{
MessageBox.Show(e.Message);
}
}
void _timer_Elapsed(object sender, ElapsedEventArgs e)
{
//If timer is elapsed I have to raise an exception
if (t != null)
{
t.Abort();
}
}
private void ConnectTo()
{
//Just an example implementation
//Do something!!
try
{
//Connect to SerialPort and wait for correct response
using (SqlConnection _SC = new SqlConnection("aaaa"))
{
_SC.Open();
}
}
catch (Exception)
{
throw;
}
finally
{
//If connected than
_timer.Stop();
}
}
}