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I am using SerialPort_DataReceived event in my project. But I want to have different Strategies of receiving data inside the body of this event.

I have googled and I found that one way is to inject the Func<> to the methods and changing their behaviour (Strategy Pattern).

But is that possible to do the same for evnets like SerialPort_DataReceived? If yes how can I do that? (without violating the principles)

Edit:

Actually I want to add Func<> Parameter to the SerialPort_DataReceived Like this:

public Rs232(string portName, int baudRate, Parity parity, int dataBits, StopBits stopBits)
        {
            SerialPort = new SerialPort(portName, baudRate, parity, dataBits, stopBits);
            SerialPort.DataReceived += SerialPort_DataReceived;
        }

        private void SerialPort_DataReceived(object sender, SerialDataReceivedEventArgs e)
        {
            throw new NotImplementedException();
        }

I want to change the SerialPort_DataReceived as the following:

private void SerialPort_DataReceived(Func<sth,sth> Strategy,object sender, SerialDataReceivedEventArgs e)
            {
                throw new NotImplementedException();
            }
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I am of the opinion that the DataReceived event handler should do one thing, receive the data. It should determine the bytes available, read that number of bytes, store those bytes in a queue or list, and exit. Remember that only one serial event can be active at a time. Put your strategy pattern in another thread or timer. – dbasnett yesterday
@dbasnett You know I have a set of devices that I have to read values from them. But I have problem with them. to read some of them I have to use the "ReadLine()" or "ReadByte" for the others I have to use "ReadExisting()" I can not use for example "ReadLine()" method for all of them. and obviously I can't change the devices. – Mehrdad Kamelzadeh yesterday
Everyone of them will accept msdn.microsoft.com/en-us/library/ms143549%28v=vs.100%29.aspx . How you decode / interpret the raw bytes is up to you. – dbasnett yesterday
@dbasnett thanks for your link but my question is whether it is possible to inject Func<> to an event like SerialPort_DataReceived at all? Imagine that I have to use different method for each device. my question is about Design Patterns and Method Injection not working with SerialPort. – Mehrdad Kamelzadeh yesterday
My point was that the event is not the place to decode data. When the event fires there may be 1 or more bytes available to be read. One other thing, it is a very bad idea to put a blocking read in the event handler. – dbasnett yesterday

2 Answers

up vote 0 down vote

If you talk about Serial Port's specific, I think this answer may not apply.

I thought of an adapter-specific pattern to handler your Method Abstraction. Assume you already know the delegation and event handler.

public class DeviceASerialPort{
    public DeviceASerialPort{
        // the parameter below may be self-defined instead of passed
        this.SerialPort = new SerialPort(portName, baudRate, parity, dataBits, stopBits);
        SerialPort.DataReceived += SerialPort_DataReceived;
    }
    private SerialPort;
    //event delegation here (i forgot how to declare delegation
    // let's say the name is also DataReceived

    private void SerialPort_DataReceived(object sender, SerialDataReceivedEventArgs e)
    {
        //null guard
        DataReceived(
            sth=> {
                //custom operation here
                return sth;
            }
            , sender
            , e);
    }
}

In the end, you can end up making interfaces for that serial port adapter or even injecting the function to extend the abstraction.

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up vote 0 down vote

Sure you can inject some Func<> to the class that contains your DataReceived event handler and call Func<> from the handler.

Also you could deliver received data to a certain handler class that has one or more Func<> to deal with data depending on decoding the raw bytes.

share|improve this answer
I don't want to inject the Fucn<> to the class containing the DataReceived. Actually I want to inject Func<> to the DataReceived Event itself (Doing something like Method Injection). – Mehrdad Kamelzadeh yesterday
1  
Are you looking for something like PostSharp? Otherwise you should post some code about what you do now and what you'd like to do. "Inject" is a bit ambigous here. – JeffRSon yesterday

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