CODEWITHSUNDEEP
c#multithreadingtimercallbackreturn
dtemps123
dtemps123

Reputation: 25

TimerCallback not returning value C#

I am using System.Threading.Timer to create a timer that prints a string to a serial port and then reads from another serial port every second. I am trying to do this by sending arguments to my TimerCallback function. Below is my code where the timer is initialized and the code for the callback function.

Initialization:

TimerCallback tcb = Timer_func(buff_out, send_port, recv_port);
AutoResetEvent autoEvent = new AutoResetEvent(false);
Timer aTimer = new Timer(tcb,autoEvent,1000,1000);

Callback function:

public static TimerCallback Timer_func(string buff_out, SerialPort send_port, SerialPort recv_port)
{
    string buff_in;
    send_port.WriteLine(buff_out);
    buff_in = recv_port.ReadLine();
    Console.WriteLine(buff_in);
}

The initialization occurs in the Main() function, and both functions are in the same class.

When I compile the code as is I recieve error CS0161: "not all code paths return a value". In attempts to remedy this I've added return 1; to the end of that function but then I recieve error CS0029: "cannot explicitly convert type 'int' to 'System.Threading.Timer'.

What am I doing wrong, and how can I fix it. (New to C#). Thank you in advance!

Upvotes: 1

Views: 1680

Answers (1)

SLaks
SLaks

Reputation: 887479

You're misunderstanding delegates.

TimerCallback is a delegate type – a type that can hold a function.
TimerCallback can only hold functions with the signature

void MethodName(Object state)

When you write

public static TimerCallback Timer_func(...) { ... }

You just declared a function that returns a TimerCallback delegate.
Thus, your function must return a function that matches TimerCallback.

You can do that using an anonymous delegate:

return delegate (object state) {
    string buff_in;
    send_port.WriteLine(buff_out);
    buff_in = recv_port.ReadLine();
    Console.WriteLine(buff_in);
};

Upvotes: 5

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