How do I use dataReceived event of the SerialPort Port Object in C

Question

I am attempting to create a small application to collect data received from an external sensor attached to COM10   I have successfully created a small C  console object and application that opens the port and streams data to a file for a fixed period of time using a for-loop  I would like to convert this application to use the dataReceived event to stream instead  After reading the Top 5 SerialPort Tips  I still can t seem to get this to work and don t know what I am missing   I rewrote the console application so that all the code is in Main and is pasted below  Can someone please help enlighten me as to why the event handler port OnReceiveDatazz is not being called even though I know that there is data being sent to the port by the hardware  Thanks Thanks to  Gabe   Jason Down  and  abatishchev for all the suggestions   I am stumped and can t seem to get the event handler to work  Perhaps it has something to do with the device   I can live with just reading the port in a thread and streaming the data straight to file   Code  namespace serialPortCollection     class Program               static void Main string   args                                     const int bufSize   2048              Byte   buf   new Byte bufSize     To store the received data               SerialPort sp   new SerialPort  quot COM10 quot   115200               sp DataReceived    port OnReceiveDatazz     Add DataReceived Event Handler              sp Open                sp WriteLine  quot   quot      Command to start Data Stream                 Wait for data or user input to continue              Console ReadLine                            sp WriteLine  quot   quot      Stop Data Stream Command             sp Close                                 My Event Handler Method         private static void port OnReceiveDatazz object sender                                      SerialDataReceivedEventArgs e                        SerialPort spL    SerialPort  sender              const int bufSize   12              Byte   buf   new Byte bufSize               Console WriteLine  quot DATA RECEIVED  quot                Console WriteLine spL Read buf  0  bufSize

User · Answer

By the way  you can use next code in you event handler   switch e EventType      case SerialData Chars             means you receives something     break        case SerialData Eof             means receiving ended     break

User · Answer

I believe this won t work because you are using a console application and there is no Event Loop running   An Event Loop   Message Pump used for event handling is setup automatically when a Winforms application is created  but not for a console app

User · Answer

By the way  you can use next code in you event handler   switch e EventType      case SerialData Chars             means you receives something     break        case SerialData Eof             means receiving ended     break

User · Answer

I was having the very same problem with a modem that had previously worked and then one day just stopped raising the DataReceived event   The solution in my case  very randomly  was to enable RTS e g   sp RtsEnable   true    No idea why that worked on this particular bit of kit  not a comms man at all really   nor why it had worked and then stopped but it may help somebody else one day so just posting it just in case

User · Answer

I believe this won t work because you are using a console application and there is no Event Loop running   An Event Loop   Message Pump used for event handling is setup automatically when a Winforms application is created  but not for a console app

User · Answer

I think your issue is the line     sp DataReceived    port OnReceiveDatazz   Shouldn t it be   sp DataReceived    new SerialDataReceivedEventHandler  port OnReceiveDatazz      Nevermind  the syntax is fine  didn t realize the shortcut at the time I originally answered this question    I ve also seen suggestions that you should turn the following options on for your serial port   sp DtrEnable   true        Data-terminal-ready sp RtsEnable   true        Request-to-send   You may also have to set the handshake to RequestToSend  via the handshake enumeration      UPDATE   Found a suggestion that says you should open your port first  then assign the event handler  Maybe it s a bug   So instead of this   sp DataReceived    new SerialDataReceivedEventHandler  port OnReceiveDatazz   sp Open      Do this   sp Open    sp DataReceived    new SerialDataReceivedEventHandler  port OnReceiveDatazz     Let me know how that goes

User · Answer

First off I recommend you use the following constructor instead of the one you currently use   new SerialPort  COM10   115200  Parity None  8  StopBits One     Next  you really should remove this code      Wait 10 Seconds for data    for  int i   0  i  lt  1000  i          Thread Sleep 10       Console WriteLine sp Read buf 0 bufSize      prints data directly to the Console     And instead just loop until the user presses a key or something  like so   namespace serialPortCollection     class Program               static void Main string   args                        SerialPort sp   new SerialPort  COM10   115200               sp DataReceived    port OnReceiveDatazz     Add DataReceived Event Handler              sp Open                sp WriteLine         Command to start Data Stream              Console ReadLine                 sp WriteLine         Stop Data Stream Command             sp Close                         My Event Handler Method         private static void port OnReceiveDatazz object sender                                      SerialDataReceivedEventArgs e                        SerialPort spL    SerialPort  sender              byte   buf   new byte spL BytesToRead               Console WriteLine  DATA RECEIVED                 spL Read buf  0  buf Length               foreach  Byte b in buf                                Console Write b ToString                               Console WriteLine                        Also  note the revisions to the data received event handler  it should actually print the buffer now   UPDATE 1    I just ran the following code successfully on my machine  using a null modem cable between COM33 and COM34   namespace TestApp       class Program               static void Main string   args                        Thread writeThread   new Thread new ThreadStart WriteThread                SerialPort sp   new SerialPort  COM33   115200  Parity None  8  StopBits One               sp DataReceived    port OnReceiveDatazz     Add DataReceived Event Handler              sp Open                sp WriteLine         Command to start Data Stream              writeThread Start                 Console ReadLine                 sp WriteLine         Stop Data Stream Command             sp Close                       private static void port OnReceiveDatazz object sender                                      SerialDataReceivedEventArgs e                        SerialPort spL    SerialPort  sender              byte   buf   new byte spL BytesToRead               Console WriteLine  DATA RECEIVED                 spL Read buf  0  buf Length               foreach  Byte b in buf                                Console Write b ToString                                     Console WriteLine                       private static void WriteThread                         SerialPort sp2   new SerialPort  COM34   115200  Parity None  8  StopBits One               sp2 Open                byte   buf   new byte 100               for  byte i   0  i  lt  100  i                                  buf i    i                            sp2 Write buf  0  buf Length               sp2 Close                        UPDATE 2    Given all of the traffic on this question recently   I m beginning to suspect that either your serial port is not configured properly  or that the device is not responding   I highly recommend you attempt to communicate with the device using some other means  I use hyperterminal frequently    You can then play around with all of these settings  bitrate  parity  data bits  stop bits  flow control  until you find the set that works   The documentation for the device should also specify these settings   Once I figured those out  I would make sure my  NET SerialPort is configured properly to use those settings   Some tips on configuring the serial port   Note that when I said you should use the following constructor  I meant that use that function  not necessarily those parameters   You should fill in the parameters for your device  the settings below are common  but may be different for your device   new SerialPort  COM10   115200  Parity None  8  StopBits One     It is also important that you setup the  NET SerialPort to use the same flow control as your device  as other people have stated earlier    You can find more info here   http   www lammertbies nl comm info RS-232 flow control html

User · Answer

I was having the very same problem with a modem that had previously worked and then one day just stopped raising the DataReceived event   The solution in my case  very randomly  was to enable RTS e g   sp RtsEnable   true    No idea why that worked on this particular bit of kit  not a comms man at all really   nor why it had worked and then stopped but it may help somebody else one day so just posting it just in case

User · Answer

I think your issue is the line     sp DataReceived    port OnReceiveDatazz   Shouldn t it be   sp DataReceived    new SerialDataReceivedEventHandler  port OnReceiveDatazz      Nevermind  the syntax is fine  didn t realize the shortcut at the time I originally answered this question    I ve also seen suggestions that you should turn the following options on for your serial port   sp DtrEnable   true        Data-terminal-ready sp RtsEnable   true        Request-to-send   You may also have to set the handshake to RequestToSend  via the handshake enumeration      UPDATE   Found a suggestion that says you should open your port first  then assign the event handler  Maybe it s a bug   So instead of this   sp DataReceived    new SerialDataReceivedEventHandler  port OnReceiveDatazz   sp Open      Do this   sp Open    sp DataReceived    new SerialDataReceivedEventHandler  port OnReceiveDatazz     Let me know how that goes

User · Answer

By the way  you can use next code in you event handler   switch e EventType      case SerialData Chars             means you receives something     break        case SerialData Eof             means receiving ended     break

User · Answer

By the way  you can use next code in you event handler   switch e EventType      case SerialData Chars             means you receives something     break        case SerialData Eof             means receiving ended     break

User · Answer

Might very well be the Console ReadLine blocking your callback s Console Writeline  in fact  The sample on MSDN looks ALMOST identical  except they use ReadKey  which doesn t lock the console

User · Answer

Be aware that there are problems using  NET C  and any COM port higher than COM9   See  HOWTO  Specify Serial Ports Larger than COM9  There is a workaround in the format       COM10  that is supported in the underlying CreateFile method  but  NET prevents using that workaround format  neither the SerialPort constructor nor the PortName property will allow a port name that begins with      I ve been struggling to get reliable communications to COM10 in C   NET  As an example  if I have a device on COM9 and COM10  traffic intended for COM10 goes to the device on COM9  If I remove the device on COM9  COM10 traffic goes to the device on COM10   I still haven t figured how to use the handle returned by CreateFile to create a C   NET style SerialPort object  if I knew how to do that  then I think I could use COM10  just fine from C

User · Answer

First off I recommend you use the following constructor instead of the one you currently use   new SerialPort  COM10   115200  Parity None  8  StopBits One     Next  you really should remove this code      Wait 10 Seconds for data    for  int i   0  i  lt  1000  i          Thread Sleep 10       Console WriteLine sp Read buf 0 bufSize      prints data directly to the Console     And instead just loop until the user presses a key or something  like so   namespace serialPortCollection     class Program               static void Main string   args                        SerialPort sp   new SerialPort  COM10   115200               sp DataReceived    port OnReceiveDatazz     Add DataReceived Event Handler              sp Open                sp WriteLine         Command to start Data Stream              Console ReadLine                 sp WriteLine         Stop Data Stream Command             sp Close                         My Event Handler Method         private static void port OnReceiveDatazz object sender                                      SerialDataReceivedEventArgs e                        SerialPort spL    SerialPort  sender              byte   buf   new byte spL BytesToRead               Console WriteLine  DATA RECEIVED                 spL Read buf  0  buf Length               foreach  Byte b in buf                                Console Write b ToString                               Console WriteLine                        Also  note the revisions to the data received event handler  it should actually print the buffer now   UPDATE 1    I just ran the following code successfully on my machine  using a null modem cable between COM33 and COM34   namespace TestApp       class Program               static void Main string   args                        Thread writeThread   new Thread new ThreadStart WriteThread                SerialPort sp   new SerialPort  COM33   115200  Parity None  8  StopBits One               sp DataReceived    port OnReceiveDatazz     Add DataReceived Event Handler              sp Open                sp WriteLine         Command to start Data Stream              writeThread Start                 Console ReadLine                 sp WriteLine         Stop Data Stream Command             sp Close                       private static void port OnReceiveDatazz object sender                                      SerialDataReceivedEventArgs e                        SerialPort spL    SerialPort  sender              byte   buf   new byte spL BytesToRead               Console WriteLine  DATA RECEIVED                 spL Read buf  0  buf Length               foreach  Byte b in buf                                Console Write b ToString                                     Console WriteLine                       private static void WriteThread                         SerialPort sp2   new SerialPort  COM34   115200  Parity None  8  StopBits One               sp2 Open                byte   buf   new byte 100               for  byte i   0  i  lt  100  i                                  buf i    i                            sp2 Write buf  0  buf Length               sp2 Close                        UPDATE 2    Given all of the traffic on this question recently   I m beginning to suspect that either your serial port is not configured properly  or that the device is not responding   I highly recommend you attempt to communicate with the device using some other means  I use hyperterminal frequently    You can then play around with all of these settings  bitrate  parity  data bits  stop bits  flow control  until you find the set that works   The documentation for the device should also specify these settings   Once I figured those out  I would make sure my  NET SerialPort is configured properly to use those settings   Some tips on configuring the serial port   Note that when I said you should use the following constructor  I meant that use that function  not necessarily those parameters   You should fill in the parameters for your device  the settings below are common  but may be different for your device   new SerialPort  COM10   115200  Parity None  8  StopBits One     It is also important that you setup the  NET SerialPort to use the same flow control as your device  as other people have stated earlier    You can find more info here   http   www lammertbies nl comm info RS-232 flow control html

User · Answer

Might very well be the Console ReadLine blocking your callback s Console Writeline  in fact  The sample on MSDN looks ALMOST identical  except they use ReadKey  which doesn t lock the console

User · Answer

First off I recommend you use the following constructor instead of the one you currently use   new SerialPort  COM10   115200  Parity None  8  StopBits One     Next  you really should remove this code      Wait 10 Seconds for data    for  int i   0  i  lt  1000  i          Thread Sleep 10       Console WriteLine sp Read buf 0 bufSize      prints data directly to the Console     And instead just loop until the user presses a key or something  like so   namespace serialPortCollection     class Program               static void Main string   args                        SerialPort sp   new SerialPort  COM10   115200               sp DataReceived    port OnReceiveDatazz     Add DataReceived Event Handler              sp Open                sp WriteLine         Command to start Data Stream              Console ReadLine                 sp WriteLine         Stop Data Stream Command             sp Close                         My Event Handler Method         private static void port OnReceiveDatazz object sender                                      SerialDataReceivedEventArgs e                        SerialPort spL    SerialPort  sender              byte   buf   new byte spL BytesToRead               Console WriteLine  DATA RECEIVED                 spL Read buf  0  buf Length               foreach  Byte b in buf                                Console Write b ToString                               Console WriteLine                        Also  note the revisions to the data received event handler  it should actually print the buffer now   UPDATE 1    I just ran the following code successfully on my machine  using a null modem cable between COM33 and COM34   namespace TestApp       class Program               static void Main string   args                        Thread writeThread   new Thread new ThreadStart WriteThread                SerialPort sp   new SerialPort  COM33   115200  Parity None  8  StopBits One               sp DataReceived    port OnReceiveDatazz     Add DataReceived Event Handler              sp Open                sp WriteLine         Command to start Data Stream              writeThread Start                 Console ReadLine                 sp WriteLine         Stop Data Stream Command             sp Close                       private static void port OnReceiveDatazz object sender                                      SerialDataReceivedEventArgs e                        SerialPort spL    SerialPort  sender              byte   buf   new byte spL BytesToRead               Console WriteLine  DATA RECEIVED                 spL Read buf  0  buf Length               foreach  Byte b in buf                                Console Write b ToString                                     Console WriteLine                       private static void WriteThread                         SerialPort sp2   new SerialPort  COM34   115200  Parity None  8  StopBits One               sp2 Open                byte   buf   new byte 100               for  byte i   0  i  lt  100  i                                  buf i    i                            sp2 Write buf  0  buf Length               sp2 Close                        UPDATE 2    Given all of the traffic on this question recently   I m beginning to suspect that either your serial port is not configured properly  or that the device is not responding   I highly recommend you attempt to communicate with the device using some other means  I use hyperterminal frequently    You can then play around with all of these settings  bitrate  parity  data bits  stop bits  flow control  until you find the set that works   The documentation for the device should also specify these settings   Once I figured those out  I would make sure my  NET SerialPort is configured properly to use those settings   Some tips on configuring the serial port   Note that when I said you should use the following constructor  I meant that use that function  not necessarily those parameters   You should fill in the parameters for your device  the settings below are common  but may be different for your device   new SerialPort  COM10   115200  Parity None  8  StopBits One     It is also important that you setup the  NET SerialPort to use the same flow control as your device  as other people have stated earlier    You can find more info here   http   www lammertbies nl comm info RS-232 flow control html

User · Answer

Be aware that there are problems using  NET C  and any COM port higher than COM9   See  HOWTO  Specify Serial Ports Larger than COM9  There is a workaround in the format       COM10  that is supported in the underlying CreateFile method  but  NET prevents using that workaround format  neither the SerialPort constructor nor the PortName property will allow a port name that begins with      I ve been struggling to get reliable communications to COM10 in C   NET  As an example  if I have a device on COM9 and COM10  traffic intended for COM10 goes to the device on COM9  If I remove the device on COM9  COM10 traffic goes to the device on COM10   I still haven t figured how to use the handle returned by CreateFile to create a C   NET style SerialPort object  if I knew how to do that  then I think I could use COM10  just fine from C

User · Answer

First off I recommend you use the following constructor instead of the one you currently use   new SerialPort  COM10   115200  Parity None  8  StopBits One     Next  you really should remove this code      Wait 10 Seconds for data    for  int i   0  i  lt  1000  i          Thread Sleep 10       Console WriteLine sp Read buf 0 bufSize      prints data directly to the Console     And instead just loop until the user presses a key or something  like so   namespace serialPortCollection     class Program               static void Main string   args                        SerialPort sp   new SerialPort  COM10   115200               sp DataReceived    port OnReceiveDatazz     Add DataReceived Event Handler              sp Open                sp WriteLine         Command to start Data Stream              Console ReadLine                 sp WriteLine         Stop Data Stream Command             sp Close                         My Event Handler Method         private static void port OnReceiveDatazz object sender                                      SerialDataReceivedEventArgs e                        SerialPort spL    SerialPort  sender              byte   buf   new byte spL BytesToRead               Console WriteLine  DATA RECEIVED                 spL Read buf  0  buf Length               foreach  Byte b in buf                                Console Write b ToString                               Console WriteLine                        Also  note the revisions to the data received event handler  it should actually print the buffer now   UPDATE 1    I just ran the following code successfully on my machine  using a null modem cable between COM33 and COM34   namespace TestApp       class Program               static void Main string   args                        Thread writeThread   new Thread new ThreadStart WriteThread                SerialPort sp   new SerialPort  COM33   115200  Parity None  8  StopBits One               sp DataReceived    port OnReceiveDatazz     Add DataReceived Event Handler              sp Open                sp WriteLine         Command to start Data Stream              writeThread Start                 Console ReadLine                 sp WriteLine         Stop Data Stream Command             sp Close                       private static void port OnReceiveDatazz object sender                                      SerialDataReceivedEventArgs e                        SerialPort spL    SerialPort  sender              byte   buf   new byte spL BytesToRead               Console WriteLine  DATA RECEIVED                 spL Read buf  0  buf Length               foreach  Byte b in buf                                Console Write b ToString                                     Console WriteLine                       private static void WriteThread                         SerialPort sp2   new SerialPort  COM34   115200  Parity None  8  StopBits One               sp2 Open                byte   buf   new byte 100               for  byte i   0  i  lt  100  i                                  buf i    i                            sp2 Write buf  0  buf Length               sp2 Close                        UPDATE 2    Given all of the traffic on this question recently   I m beginning to suspect that either your serial port is not configured properly  or that the device is not responding   I highly recommend you attempt to communicate with the device using some other means  I use hyperterminal frequently    You can then play around with all of these settings  bitrate  parity  data bits  stop bits  flow control  until you find the set that works   The documentation for the device should also specify these settings   Once I figured those out  I would make sure my  NET SerialPort is configured properly to use those settings   Some tips on configuring the serial port   Note that when I said you should use the following constructor  I meant that use that function  not necessarily those parameters   You should fill in the parameters for your device  the settings below are common  but may be different for your device   new SerialPort  COM10   115200  Parity None  8  StopBits One     It is also important that you setup the  NET SerialPort to use the same flow control as your device  as other people have stated earlier    You can find more info here   http   www lammertbies nl comm info RS-232 flow control html

User · Answer

I think your issue is the line     sp DataReceived    port OnReceiveDatazz   Shouldn t it be   sp DataReceived    new SerialDataReceivedEventHandler  port OnReceiveDatazz      Nevermind  the syntax is fine  didn t realize the shortcut at the time I originally answered this question    I ve also seen suggestions that you should turn the following options on for your serial port   sp DtrEnable   true        Data-terminal-ready sp RtsEnable   true        Request-to-send   You may also have to set the handshake to RequestToSend  via the handshake enumeration      UPDATE   Found a suggestion that says you should open your port first  then assign the event handler  Maybe it s a bug   So instead of this   sp DataReceived    new SerialDataReceivedEventHandler  port OnReceiveDatazz   sp Open      Do this   sp Open    sp DataReceived    new SerialDataReceivedEventHandler  port OnReceiveDatazz     Let me know how that goes

User · Answer

I think your issue is the line     sp DataReceived    port OnReceiveDatazz   Shouldn t it be   sp DataReceived    new SerialDataReceivedEventHandler  port OnReceiveDatazz      Nevermind  the syntax is fine  didn t realize the shortcut at the time I originally answered this question    I ve also seen suggestions that you should turn the following options on for your serial port   sp DtrEnable   true        Data-terminal-ready sp RtsEnable   true        Request-to-send   You may also have to set the handshake to RequestToSend  via the handshake enumeration      UPDATE   Found a suggestion that says you should open your port first  then assign the event handler  Maybe it s a bug   So instead of this   sp DataReceived    new SerialDataReceivedEventHandler  port OnReceiveDatazz   sp Open      Do this   sp Open    sp DataReceived    new SerialDataReceivedEventHandler  port OnReceiveDatazz     Let me know how that goes

[c#] How do I use dataReceived event of the SerialPort Port Object in C#?

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