I have a problem that i cant solve i am trying to buffer 28 bytes from the com port into the array actual_packet_VPS1(30). It works with the counter set to 0 - 15 but doesnt work when we increase the counter size to 0 -28.
Private Sub MSComm5_OnComm(ByVal eventSender As System.Object, ByVal eventArgs As System.EventArgs) Handles MSComm5.OnComm
Dim buffer As Object
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The relevant code below is not achieving what I hoped it would. I intend for
1. SerialPortBufferTemp to be used as the container for each Serial Port Read.
2. _buffer should contain the resultant array from two separate Reads, the second appended directly after the first.
(E.g. 60 bytes read on the 2nd Read will be appended to the 168 bytes received on the first Read (228 total resultant byte length))
The problem with my code below is that _buffer has increase in size from 300 bytes to 600 bytes, skipped bytes 168 to 300 (leaving them all zeros) and added the remaining 60 bytes from the second read beginning at _buffer[300].
private List<byte> _buffer = new List<byte>();
byte[] SerialPortBufferTemp = new byte[300];
serialPort1.Read(SerialPortBufferTemp, 0, iBytesRead);
if (iValidRecordCtr == 0) {
_buffer.Clear();
[Code] .....
I am trying to communicate with an Extech 421509 Thermometer via the serial port.Since I do not know VB very well I first wrote the program in LabVIEW to make sure I knew how to write the program, once I was successful with that I tried to write the code in VB.I am mostly successful with that except that in VB my buffer will be read 4 or 5 times and then there is nothing on my buffer. In LabVIEW I do not have this problem as I write to the buffer I can immediately read from the buffer.
Imports System
Imports System.IO.Ports
Imports System.Threading[code]....
Does reading the serial port empty the buffer?
View 2 Repliesi have a program that sniffs for packets on a port going to a specific address on my lan and then sends an exact copy to the same address on another port, the problem is when i edit the port bytes in the TCP packet i have to regenerate the checksum, and thats where the problem comes in, everything i have researched on this just doesnt make sense to mei am looking for a function that will output the checksum and a little explanation on what i need to put in for it to come out right
View 1 RepliesI'm working with a device using the serial port and i am sending a command from the pc to the device like this:
1. I Change the parity to mark
2. then send a byte
3. then Change the parity to space (here is the problem)
4. Send a lot of bytes
but the device just ignores all the last bytes, im pretty sure its a timing problems, so a timeout occurred attempting to send a command, how can i change the parity without losing time?
I'm using 2008 Express and I'm trying to send 1 byte of data on the serial port.
Serialport1.write(123) Sends 3 bytes with the ascii codes representing 1 2 and 3.
I want to send 1 byte that contains 123.
In my serial port application, I have my code -
Private Sub SerialPort_DataReceived(ByVal sender As System.Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles SerialPort.DataReceived
Dim cnt2 As Byte
[code]....
For some packets I sent, "Error Data Received" came up. I checked BytesReceived, it was 0. My question is: since SerialPort_DataReceived processes data received, data was supposed to be received. Why the number of bytes I read was zero? BTW, when is this event accessed? it is accessed when any number of bytes received or the whole packet received?
I have a timer control that sends data to a hardware every 3 seconds. I sent 6 bytes of data. In return I am expecting 8 bytes of data in DataReceived event. First time I send 6 bytes of date, in DataReceived event, I get the expected 8 bytes. Then in next 3 seconds, again the expected 8 bytes of data is received. But after that I find that DataReceived is fired 2 times: first time I get 6 bytes and then I get 2 bytes. After that I again get 8 bytes as expected. So in short, 2 times I get 8 bytes as expected and 6 bytes and 2 bytes and again 8 bytes. This pattern is repeating continuously. Why? Is there any reason why I cannot get all 8 bytes everytime? Note that the code is in vb.net 2008
Code in button btn_Start ()
'Set serial port parameters
x.PortName = "COM1"
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I'm working on a project involving reading RFID tags, I've written the code and it reads the tags ok by using the recieved data handler and displaying the result in a listbox, the only problem is that the data displayed has a couple of unreadable characters at the start (I'm using ReadLine() command.)If I read the buffer byte by byte the data is all readable.How can I read and display the whole 16 Bytes in one go??
View 3 RepliesI have textbox with vbscript, user could type integers, then hit return key, KeyUp event for return would trigge theWriteFile()being called for com port to write string to the device, if Ihit return key slow, I would get 0bytewritten for WriteFile(), timeout happening basically,if I hit return keyquick,
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This is my code for retrieving pictures, it was working before but then i accidentally deleted the table and i created it again with the same name and same fields. and now whenever i open the form with the picture, there was a message box error. it says Buffer cannot be null. Parameter name: buffer I don't know what i did wrong.
I want it to do is that you input a string, then you select an algorithm (Theres only going to be one RijnDael) then you input a key, then the Initialization Vector comes from "txtIV.text" then you select the key bytes and the block bytes from the numeric up/down, then you either encrypt or decrypt.
View 1 RepliesOk i am having some issues designing a base-class to handle generics.Caveat is i need to restrict the type put in as a Numeric type, specifically Int16, Int32, or Int64 (Short or Long).I know you can do Of T as {Structure} but i dont want to select the key bytes and the block bytes from the numeric up/down.
View 2 RepliesI keep getting a ProtocolViolationException "Bytes to be written to the stream exceed the Content-Length bytes size specified." on the following code.I've tried setting Content-Length numerous ways with no success.
Dim url = "https://domain.com"
Dim req As WebRequest = WebRequest.Create(url)
req.Method = "POST"
req.ContentType = "application/xml"
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What exactly does this line do?
i = stream.Read(bytes, 0, bytes.Length)
Does it read the entire message string sent by the client? I have a line to write to the stream later in the code and that does not seem to be sending anything back to the client, although the code around is excuting.
i = stream.Read(bytes, 0, bytes.Length)
While (i <> 0)
Try
' Translate data bytes to a ASCII string.
[code].....
I created a text file contains 4 bytes of data
AABBCCDD
I just want to read the first 2 bytes (AABB) to execute it with my program.
Then I'll need to read the last 2 bytes (CCDD) for another computer routines
Probably missing something silly here, Her eis what my display looks like Sending image...(401303) I would prefer it displays as Sending image...(391 kb)
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I'm mohammed from Oman ,I'm visual studio.net programmer How I can Read the Data From Barcode Weight scales By Serial port and TcpIp port
View 7 RepliesI have a Windows form.in windows form have a combo box that give me a list of available port serial with it code (Dim ports As String() =SerialPort.GetPortNames())for example( Com1,Com8,Com15,...).but I want to give me fullname of serial port in device manager for example in dvice manager is these (Comunication Port(COM1) - Printer Port(LPT1) And USB Serial Port(COM8)).how to Get it?
View 2 RepliesI would like to detect the Address and Port number of the Parallel Port in computer.
View 4 RepliesIf I uninstall the COM1 and reboot, it works. If I shut down (power off) and restart, I get the message below. If I uninstall then click on Scan for Hardware Changes,The given port name does not start with COM/com or does not resolve to a valid serial port. Parameter name:portName
View 8 RepliesI am trying to get my 4 port USB relay board to work in VB.net using the COM PORT. I found some code from a poster who has the 16 port USB relay version. When trying his code i can only get it to turn on relays 1-3 all at the same time. The product can be found here: USB 4 port relay
"01+//" - Relay 1 is switched ON
"01-//" - Relay 1 is switched OFF
"02+//" - Relay 2 is switched ON
"02-//" - Relay 2 is switched OFF
[code].....
So i am confused as to how to separate each relay out with that code above and just be able to turn on any number 1-4 relay on or off independently from each other!
To Double Buffer or not to Double Buffer this is the Question!I have a form with Protected Overrides Sub OnPaint that sets forms background to a gradient fill ,on top of that is a transparent richtext box.
Ok. now here`s the problem ,If i enable forms double buffering the transparent Rtb doesn't flicker when forms resized. but the forms drop shadow does flicker! ,its a boarderless form using CS_DROPSHADOW to draw the drop shadow Now if i disable double buffering the forms drop shadow doesn`t flicker but the transparent Rtb does ,any one have a clue how to get both to work in harmony !
The reply buffer is in ASCII value...but I need is HEX value.Is there any way that the reply buffer is in hex?
Code:
Public Function read_write_string(ByVal devicehandle, ByVal command, ByVal commandlenght) As String
Dim inputReportBuffer(100) As Byte
unManagedBuffer = Marshal.AllocHGlobal(inputReportBuffer.Length)
[code]....
I have a need to double buffer a flowlayoutpanel. I have the form set to doublebuffered which is half the story but their is no property in the list to make the flowlayoutpanel do this (although MSDN states that it has this property) how i can set it to true for the panel?
View 5 RepliesIm trying to do a video player but i have to play this video from the buffer, is this possible.. Let me explain you much more complicated,a got a CryptoStream and im decryting the video
While lngBytesProcessed < lngFileLength
'Read file with the input filestream.
intBytesInCurrentBlock = fsInput.Read(bytBuffer, 0, 4096)
'Write output file with the cryptostream.
[code]....
This code writes my decryted or crypted video to a new file. However, i need to play the video file from the buffer(without copying to a new file), in other way it would be meaningless if i create a decryted file. in other words it would unsecure for me cuz if anyone can locate my temp directorey they can copy my decrypted video files.
Dim Fs as FileSystemObject
Dim TS as TextStream
Set Fs = CreateObject("Scripting.FileSystemObject")
Set Ts = fs.OpenTextFile(textFilePath, ForReading, False,
TristateUseDefault)
While not Ts.AtEndOfStream
Buffer=Ts.ReadLine
' Process the buffer
Wend
Ts.Close
Fs.Close
I tried to convert into c# but am getting ERROR like EOF expected, what I have to do?
I am using VB.net sockets to send a music file from one instance to another. It currently saves the file, but I do not want to be caught up in file-sharing, so I want to "save" it to a buffer, and when it gets to a particular percentage transferred, I want another thread to play the music file, deleting it from the buffer as it plays. I have the code to send it over the network, but I need to know how to keep it in a buffer and not save it as a file.
View 1 RepliesI've looked and looked + tryed debugging but I'm not getting anywhere fast I'm trying to import a usb radio driver and I'm 99% there. I can turn it on / off and get / set the freq.. but I'm struggling to get the rds name from it. The VB code for the function is
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