C++/CLI reading Binary From a Serial port

Question

4.00/5 (1 vote)

See more:

I have written code to read strings via the serial port, But now i need to alter it to read binary inputs.

Here is what I have at the moment

C#

private: System::Void serialPort1_DataReceived(System::Object^  sender, System::IO::Ports::SerialDataReceivedEventArgs^  e) {
             if (_continue == true)
             {

                    String^ data = serialPort1->ReadExisting();             //Reading all exsisting data in serialport buffer
                    StreamWriter^ sw= File::AppendText(fileloc->Text);      //Seting stream wirter up and pointing to selected file
                    sw->Write(data);                                        //write data to same line
                    this->databox->AppendText(data);                        //write data to rich text box

                    sw->Flush();                                            
                    sw->Close();
             }
         }

This is some of the changes that I have made

C#

private: System::Void serialPort1_DataReceived(System::Object^  sender, System::IO::Ports::SerialDataReceivedEventArgs^  e) {
             if (_continue == true)
             {

                    int data= serialPort1->ReadByte();
                    BinaryWriter^ bw = gcnew BinaryWriter( File::Open(fileloc->Text,FileMode::Append));
                    bw->Write(data);
                    //this->databox->AppendText(data);       Not started on writing binary to the Rich text box

                    bw->Flush();
                    bw->Close();
             }
         }

Thanks for any help!

Posted 21-Apr-11 10:24am

Member 7796364

Updated 21-Apr-11 10:41am

Graham Shanks

v2

Add a Solution

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Nish Nishant · Accepted Answer · 2011-04-21T10:30:00

Solution 1

You need to call ReadByte in a loop until it returns -1. And then you can probably use File::WriteAllBytes to write it to a file. If you want to append to the file, you'd need to write more code (something similar to what you already have now.

And I don't think it makes sense to display binary data in a rich text box.

[Update]
--------

Example Read usage:

C++

// 100 and 75 are arbitrary values for the sake of the example. 
// Do not hardcode this in your code.
array<byte>^ bytes = gcnew array<byte>(100);
serialPort->Read(bytes, 0, 75);

Posted 21-Apr-11 10:30am

Nish Nishant

Updated 22-Apr-11 4:25am

v3

Comments

Sergey Alexandrovich Kryukov 21-Apr-11 16:46pm

It's a solution, my 5.
--SA

Nish Nishant 21-Apr-11 16:49pm

Thanks SA!

Rick Shaub 21-Apr-11 16:47pm

You can also call Read() into a byte buffer of arbitrary size. It won't block because we already know that there's data available.

Nish Nishant 21-Apr-11 16:49pm

Thanks Rick, I trust the OP will take your comment into consideration.

Member 7796364 21-Apr-11 17:03pm

Sorry I am pretty new at programing. Looking at MSDN it shows Read(array<byte>, Int32, Int32)
Not sure how to populate Read() for my example.

Nish Nishant 21-Apr-11 17:07pm

That assumes you know the count of bytes that are coming in. Or at least the max count. So for example, you could pass 256 for count when you know that the max will be less than that. Makes sense?

Member 7796364 22-Apr-11 10:09am

Yes the array needs to be longer enough to hold the data.
How would the code look for the line? what i have tried has not worked.

tried variations

int data = serialPort1->Read(array<system::byte>, int offset, int count);

this setup give me error C2275: 'cli::array<type>' : illegal use of this type as an expression

Nish Nishant 22-Apr-11 10:25am

I've updated my answer with an example code snippet.

Member 7796364 22-Apr-11 10:34am

Thanks, to make sure I have this right. bytes is now an array of 100. then we are reading the serial port filling the bytes array with 75 bytes and 0 offset.

thanks for all this help.

Nish Nishant 22-Apr-11 10:35am

Yeah, that's correct.

Member 7796364 21-Apr-11 16:55pm

Writing to the rich text box is only to see if it is working. Would i need to write a loop? The data ReceivedEvent should run every time data is received(?)

Nish Nishant 21-Apr-11 17:01pm

The loop's needed for multiple bytes. Although you could use the overload Rick mentioned above to do it one go.