C# Timer WinForms

Question

Hello,

 public System.Threading.Timer AsyncProgramChangeTimer = null;
        public void MyStartTimer()
        {
            lock (this)
            {
                AsyncProgramChangeTimer = new System.Threading.Timer((o) =>
                {
                    if (ProgramChangeDone == false)
                    {
                        //do whatever
                        Trace.WriteLine("Timer was coming!!!");
                        Action<string> DelegateTeste_ModifyText = THREAD_MOD;
                        Invoke(DelegateTeste_ModifyText, $"Timer was coming!!! {DateTime.Now}");
                        AsyncProgramChangeTimer.Change(2000, Timeout.Infinite);
                    }
                    else
                    {
                        Trace.WriteLine("Timer no repeat!!!");
                    }
                }, null, 0, Timeout.Infinite);
            }
        }


 private void THREAD_MOD(string test)
        {
            txtStatus.Text += Environment.NewLine + test;
        }


  private void btnStopTimer_Click(object sender, EventArgs e)
        {
            ProgramChangeDone = !ProgramChangeDone;
            MyStartTimer();
        }

My goal.

A) Action or Func
How do I have to write it if I want a return value?

How do I have to write it if I want to have one return value and two passing parameters?

How do I have to write it if I want to have no return value and three passing parameters?

B) Lock
Do I need the lock so no one can access it?

C) Via a button I would like to switch the timer monitoring on or off.

D) Invoke or Dispatcher ?
Update the controls, which mechanism is correct?
Is this correct in my example?

Answer 1

@Markus Freitag , Welcome to Microsoft Q&A,

A:
Action delegate doesn't return the value and Func delegate can return one result.

Example:

(no parameter and return one value)

 Func<string> delegatechangetest = Changetext;  
 string result = delegatechangetest();  
  
  private string Changetext()  
        {  
            string result = Environment.NewLine+sometext;  
            return result;    
        }  

(Two parameters and return one value)

 Func<string, string, string> delegatechangetest = Changetext;  
  string result = delegatechangetest($"Timer was coming!!! {DateTime.Now}", "yes");  
  
 private string Changetext(string test1, string test2)  
        {  
            string result = Environment.NewLine + test1 + test2;  
            return result;    
        }  

B:
Yes, you could use lock to stop any other thread to acquire the lock until the lock is released.

C:
Please try the following code to use a button to stop or start the timer:

private void button1_Click(object sender, EventArgs e)  
        {  
            ProgramChangeDone = !ProgramChangeDone;  
            if(AsyncProgramChangeTimer==null)  
            {  
                MyStartTimer();  
            }  
            else  
            {  
                AsyncProgramChangeTimer.Change(Timeout.Infinite, Timeout.Infinite);  
                AsyncProgramChangeTimer = null;  
            }  
                  
        }  

D:
You could use Invoke or Dispatcher both to update the control:

Invoke:

 Func<string, string, string> delegatechangetest = Changetext;  
 string result = delegatechangetest($"Timer was coming!!! {DateTime.Now}", "yes");  
 txtStatus.Invoke((MethodInvoker)delegate { txtStatus.Text += result; });  

Dispatcher:

Func<string, string, string> delegatechangetest = Changetext;  
 string result = delegatechangetest($"Timer was coming!!! {DateTime.Now}", "yes");  
  Dispatcher dispUI = Dispatcher.CurrentDispatcher;  
  DispatcherOperation dispatcherOperation = dispUI.BeginInvoke(DispatcherPriority.Normal, (MethodInvoker)delegate { txtStatus.Text += result; });  

I think your code example is enough to get what you want except the button to start or stop the timer.
Full completed code example:( Use Function delegate:)

public System.Threading.Timer AsyncProgramChangeTimer = null;  
public void MyStartTimer()  
{  
    lock (this)  
    {  
        AsyncProgramChangeTimer = new System.Threading.Timer((o) =>  
        {  
        if (ProgramChangeDone == false)  
        {  
            //do whatever  
            Console.WriteLine("Timer was coming!!!");  
            //Action<string, string> DelegateTeste_ModifyText = THREAD_MOD;  
            //Invoke(DelegateTeste_ModifyText, $"Timer was coming!!! {DateTime.Now}", "yes");  
            Func<string, string, string> delegatechangetest = Changetext;  
            string result = delegatechangetest($"Timer was coming!!! {DateTime.Now}", "yes");  
            txtStatus.Invoke((MethodInvoker)delegate { txtStatus.Text += result; });  
                //Dispatcher dispUI = Dispatcher.CurrentDispatcher;  
                //DispatcherOperation dispatcherOperation = dispUI.BeginInvoke(DispatcherPriority.Normal, (MethodInvoker)delegate { txtStatus.Text += result; });->Use dispatcher to update control  
            AsyncProgramChangeTimer.Change(2000, Timeout.Infinite);  



            }  
            else  
            {  
                Console.WriteLine("Timer no repeat!!!");  
            }  
        }, null, 0, Timeout.Infinite);  
    }  
}  
public bool ProgramChangeDone = true;  

private string Changetext(string test1, string test2)  
{  
    string result = Environment.NewLine + test1 + test2;  
    return result;    
}  
private void THREAD_MOD(string test1,string test2)  
{  
    txtStatus.Text += Environment.NewLine + test1+test2;  
}  

private void button1_Click(object sender, EventArgs e)  
{  
    ProgramChangeDone = !ProgramChangeDone;  
    if(AsyncProgramChangeTimer==null)  
    {  
        MyStartTimer();  
    }  
    else  
    {  
        AsyncProgramChangeTimer.Change(Timeout.Infinite, Timeout.Infinite);  
        AsyncProgramChangeTimer = null;  
    }  
          
}  

Best Regards,
Jack

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