How to write port serial

Question

1.00/5 (1 vote)

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The code below returns the error:
System.FormatException Error: The input string was not in a correct format.

What I have tried:

C#

SerialPort sp = new SerialPort();
sp.PortName = "COM3";
sp.BaudRate = 9600;
sp.Parity = Parity.None;
sp.DataBits = 8;
sp.StopBits = StopBits.One;
sp.Open();
byte[] bytestosend = { 0x1B, byte.Parse("?"), 0x1B, 0xA2, byte.Parse("748"), 0x0D, 0x1B, 0xA3, byte.Parse("1200,00"), 0x0D, 0x1B, 0xA4, byte.Parse("11/10/2019"), 0x0D, 0x1B, 0xA1, byte.Parse("CHICOBEL"), 0x0D, 0x1B, 0x1B, 0xB0, 0x0D };

sp.Write(bytestosend, 0, bytestosend.Length);

Posted 11-Oct-19 1:42am

Gilcecler Carneiro

Updated 15-Oct-19 2:46am

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Comments

ZurdoDev 11-Oct-19 7:47am

Which line causes the error?

phil.o 11-Oct-19 7:53am

What are you expecting from snippets like byte.Parse("?") or byte.Parse("11/10/2019") to produce?
byte corresponds to an unsigned 8-bits value, you cannot fit anything in there.

3 solutions

Solution 2

Each of these expressions causes an exception:

byte.Parse("?")
byte.Parse("748")
byte.Parse("1200,00")
byte.Parse("11/10/2019")
byte.Parse("CHICOBEL")

e.g. byte.Parse("748") results in 'Value was either too large or too small for an unsigned byte.

e.g. byte.Parse("CHICOBEL") results in 'Input string was not in a correct format.'

Each argument must be a number which fits into the unsigned byte type.

'?' is not a number
'1200,00' is a number, but too big
'11/10/2019' is not a number
'CHICOBEL' is not a number
'748' is a number, but too big

As Byte Struct in C# - GeeksforGeeks[^] says a byte can hold a number between 0 and 255.

In order to split any data type to bytes you can use the BitConverter class:
BitConverter Class (System) | Microsoft Docs[^]

Posted 11-Oct-19 2:01am

TheRealSteveJudge

Updated 11-Oct-19 2:18am

v2

Comments

Gilcecler Carneiro 11-Oct-19 8:07am

in java i make a for
in C # does the write command not print byte by byte?

besides hex commands I need to send byte by byte the values "1200.00" "748" etc

//java
stValue = "748"; //Banco

btCmds[1] = (byte)0xA2;

btCmds[0] = 0x1B;

for(wdCnt=0;wdCnt < stValue.length() ;wdCnt++ )

{ btCmds[wdCnt+2] = stValue.getBytes()[wdCnt]; }

btCmds[wdCnt+2] = 0x0D;

szCmds = wdCnt+3;

for(int Count = 0;Count < szCmds; Count ++) //Envia Dados

serialPort.writeByte(btCmds[Count]);

stValue = "123456,00"; //Valor

obReg.Valor = stValue;

btCmds[1] = (byte)0xA3;

btCmds[0] = 0x1B;

for(wdCnt=0;wdCnt < stValue.length() ;wdCnt++ )

{ btCmds[wdCnt+2] = stValue.getBytes()[wdCnt]; }

btCmds[wdCnt+2] = 0x0D;

szCmds = wdCnt+3;

for(int Count = 0;Count < szCmds; Count ++) //Envia Dados

serialPort.writeByte(btCmds[Count]);

TheRealSteveJudge 11-Oct-19 8:15am

If you read the Java code thoroughly you will find that a "getBytes" method is used.
This converts e.g. '123456,00' into a byte array.
You must do the same by using the BitConverter Class

https://docs.microsoft.com/en-us/dotnet/api/system.bitconverter?view=netframework-4.8

Gilcecler Carneiro 11-Oct-19 9:37am

@TheRealSteveJudge - very important your remark, helped me a lot, thanks :)

Gilcecler Carneiro 11-Oct-19 8:55am

hummmm, should i do the same loop save in matrix? I'll try

Solution 3

is correct ?

didn't entry in for

C#

SerialPort sp = new SerialPort();
                sp.PortName = "COM3";
                sp.BaudRate = 9600;
                sp.Parity = Parity.None;
                sp.DataBits = 8;
                sp.StopBits = StopBits.One;
                sp.Open();
                
                byte[] btCmds = new byte[200];

                btCmds[1] = 0xA3;
                btCmds[0] = 0x1B;

                stValue = "123456,00"; //Valor
                MessageBox.Show("tamanho " + stValue.Length);

                for (wdCnt = 0; wdCnt < stValue.Length; wdCnt++)
                {
                    stValuep=stValue.Substring(wdCnt);
                    MessageBox.Show("substring  " + stValuep);
                    
                        
                    btCmds[wdCnt + 2] = byte.Parse(stValuep); 
                }

                               
                btCmds[wdCnt + 2] = 0x0D;

                szCmds = wdCnt + 3;

                //for (int Count = 0; Count < szCmds; Count++)   //Envia Dados

                MessageBox.Show("vetor byte " + btCmds);

                    sp.Write(btCmds, 0, btCmds.Length);

Posted 15-Oct-19 2:47am

Gilcecler Carneiro

Comments

Richard MacCutchan 15-Oct-19 9:23am

No it is not correct, you need to add the length value to the stValue.Substring call:
stValuep=stValue.Substring(wdCnt, 1);
However, that will still fail when it tries to parse the comma. Also it is not clear exactly what format the value needs to be in when it is passed to the serial port device, and that may very well be crucial.

Gilcecler Carneiro 15-Oct-19 15:32pm

*************************************************************
Printer Manual

Function: Command / Format (HEX):
Send value to print 1Bh A3h 'VALUE' 0Dh
*******************************************************
for example:
I want to report the value of $ 1200.00
I need to send the "."

stValue = "1200.00"; //Valor

for (wdCnt = 0; wdCnt < stValue.Length; wdCnt++)
{
stValuep=stValue.Substring(wdCnt);
MessageBox.Show("substring " + stValuep);
btCmds[wdCnt + 2] = byte.Parse(stValuep);
}

btCmds[wdCnt + 2] = 0x0D;

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Richard MacCutchan · Accepted Answer · 2019-10-11T01:49:00

Solution 1

C#

byte.Parse("1200,00")
byte.Parse("CHICOBEL")

Byte.Parse Method (System) | Microsoft Docs[^] only accepts integer values in the string.

Posted 11-Oct-19 1:49am

Richard MacCutchan

Comments

TheRealSteveJudge 11-Oct-19 8:02am

5*, but also the allowed range of 0 to 255 must be respected.

Richard MacCutchan 11-Oct-19 8:14am

Thank you for noting that.