C# Timer, Event with int and string variable

Question

C# Timer, Event with int and string variable

Markus Freitag 3,791

Hello,

I need to trigger an event with two variables from a timer thread. How can I implement this well?

int as error number

string as message

If I throw an exception within the timer, the application hangs.

Thanks for your help!

Event int, string

Reza Aghaei 4,986 Reputation points MVP Volunteer Moderator

2023-01-19T16:38:41.0566667+00:00

How the tread has been created?

Markus Freitag 3,791

I use this.

Thanks for your help. How can I trigger an event with multiple variables.

Maybe you can post some code.

public Timer AsyncProgramChangeTimer = null;  
        public void MyStartTimer()  
        {  
            lock (this)  
            {  
                //AsyncProgramChangeTimer = new Timer((o) =>  
                //{  
                //    lock (this)  
                //    {  
                //        AsyncPendingProgramId = null;  
                //    }  
                //}, null, 5000, Timeout.Infinite);  
  
                AsyncProgramChangeTimer = new Timer((o) =>  
                {  
                    lock (this)  
                    {  
                        AsyncPendingProgramId = null;  
                    }  
                }, null, 1000, 0);  
  
            }  
  
        }

Reza Aghaei 4,986 Reputation points MVP Volunteer Moderator

2023-01-19T20:05:16.46+00:00

I provided an example that works in WinForms.

1 answer

Your answer

Reza Aghaei 4,986 Reputation points MVP Volunteer Moderator

2023-01-19T16:38:41.0566667+00:00

How the tread has been created?
Markus Freitag 3,791 Reputation points

2023-01-19T16:53:48.28+00:00

I use this.

Thanks for your help. How can I trigger an event with multiple variables.

Maybe you can post some code.

public Timer AsyncProgramChangeTimer = null; public void MyStartTimer() { lock (this) { //AsyncProgramChangeTimer = new Timer((o) => //{ // lock (this) // { // AsyncPendingProgramId = null; // } //}, null, 5000, Timeout.Infinite); AsyncProgramChangeTimer = new Timer((o) => { lock (this) { AsyncPendingProgramId = null; } }, null, 1000, 0); } }
Reza Aghaei 4,986 Reputation points MVP Volunteer Moderator

2023-01-19T20:05:16.46+00:00

I provided an example that works in WinForms.

Answer 1

Reza Aghaei 4,986 MVP Volunteer Moderator

Assuming you have a Form1 like this:

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }
    public void HandleError(int errorCode, string errorMessage)
    {
        this.Text = $"{errorCode}: {errorMessage} - " +
            $"{DateTime.Now.ToLongTimeString()}";
    }
}

And a Program.cs like this:

internal static class Program
{
    public static Form1 MainForm { get; private set; }
    /// <summary>
    /// The main entry point for the application.
    /// </summary>
    [STAThread]
    static void Main()
    {
        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);
        MainForm = new Form1();
        Application.Run(MainForm);
    }
}

The following piece of code throws and exception every two seconds, and updates the Text of your main form:

System.Threading.Timer timer = new System.Threading.Timer(
    (o) =>
    {
        try
        {
            //do something
            int i = 1;
            i = i / (i - 1);
        }
        catch (Exception)
        {
            Program.MainForm?.Invoke(new Action(() =>
            {
                Program.MainForm.HandleError(1, "Devide by zero");
            }));
        }
    }, null, 0, 2000);

Markus Freitag 3,791

This works very well. Thank you very much.

But now if I have no window, only a class, say batch.

List<int, Batch> ListProcess;
public class Batch
{
    int Quantity;
	string Name;
	string Supplier;
	int Age;
	DateTime ExpiryDate;
	
	void StartTimerExceptionTest();
	
	public void HandleError(int errorCode, string errorMessage)
        {
            Trace.Writeline($"{errorCode}: {errorMessage} - " +
                $"{DateTime.Now.ToLongTimeString()})";
        }
	
}

Then I have no invoke.

private void StartTimerExceptionTest()
 {
 System.Threading.Timer timer = new System.Threading.Timer(
(o) =>
{
	try
	{
		//do something
		int i = 1;
		i = i / (i - 1);
	}
	catch (Exception)
	{

	//	Program.MainForm?.Invoke(new Action(() =>
    //   Not possible

		Program.MainForm?.Invoke(new Action(() =>
		{
			Program.MainForm.HandleError(1, "Devide by zero");
		}));
	}
}, null, 0, 2000);
}

Jack J Jun 25,296 Reputation points

2023-02-01T06:29:02.3833333+00:00

@Markus Freitag ,

But now if I have no window, only a class, say batch.

If the app has no window, does your app still hang? If your timer has no Interaction with the UI thread, the app will not be blocked.

Reza Aghaei 4,986 MVP Volunteer Moderator

@Markus Freitag The question is about interaction between a thread and the UI thread. If you do not have a UI thread the replace that piece of code with whatever makes sense for your application. In general, you can replace above code with invoking an Action<Exception> and

For example:

Action<Exception> logAction; //Assign in to something that fits your requirements
System.Threading.Timer timer = new System.Threading.Timer(
    (o) =>
    {
        try
        {
            //do something
            int i = 1;
            i = i / (i - 1);
        }
        catch (Exception ex)
        {
            logAction(ex);
        }
    }, null, 0, 2000);

In my example, the action was like this (without using the exception parameter):

Action<Exception> logAction  = (ex) => {
    Program.MainForm?.Invoke(new Action(() =>
    {
        Program.MainForm.HandleError(1, "Devide by zero");
    }));
};

You do something else, for example:

Action<Exception> logAction  = (ex) => {
    System.IO.File.WriteAllText("c:\\log.txt", ex.ToString());
};

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C# Timer, Event with int and string variable

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