IO.Ports.SerialPort - Writes Fine, Reads Proving?
Jan 24, 2012
I'm having a bit of trouble with the SerialPort class I'm hoping someone might be able to shed some light on. Specifically, writing to the port appears to work without incident. However, reading data is proving problematic. Initially I thought it was my hardware, but testing suggested the fault lied in software. I was able to confirm this with the installation of a loopback device on the port. It tends to be missing bytes, inserting bad bytes, and shifting bytes randomly.
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Feb 17, 2010
I'm launching my application at the end of installation using custom installer class - Sub oncommited.I'm using vb 2005 setup project.The application main form load event need to read/write values from HKCUSoftwareMyApp registry.The problem is that when the application is launched at the end of installation ,it reads/writes from HKEY_Users.DefaultSoftwareMyApp instead of HKCU though I've written
My .Computer.Registry.CurrentUser.CreateSubKey(RegKey).GetValue("Name","")
When the application is launched through Program files shortcut,it reads/writes properly.I need to exit the application depending on registry values.
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Feb 24, 2010
I'm currently finishing up a project that reads / writes to an access database. The only issue I'm having is that it needs to have the file path to the database file. EX:
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Mar 15, 2009
I am writing an app that reads from the com port, filters the data, then writes to the text box, then immediately starts over. This all takes place in an endless " do while" loop within the "start" button code. I also have a end button too which closes the com port and ends the program. Some other buttons are present also to change the filter settings.Problem is when I click start, data is logged, but none of the other buttons work. Also some of the text boxes are "see through" and dont look like thy have updated with the rest of the form.
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Oct 4, 2010
I should create a program for a Pocket PC that reads & writes data from an MSAccess database located on a desktop computer (pocket PC and desktop one are connected through a Wi-Fi connection).Is that possible?
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Jun 3, 2010
How can I make multiple instances of System.IO.Ports.SerialPort and declare them on the fly? I need to monitor multiple RS232 ports based on the EU's selection. EU will select ports e.g. 1,2,6,9,11 and rename them as necessary. Selections will then be stored in a settings file.I would like to declare these at runtime e.g
Com1 is renamed LabelPrinter
Dim comLabelPrinter As New System.IO.Ports.SerialPort
With comLabelPrinter
[code]....
Or if not, make multiple instances based on the number of ports selected and renamed.The declaration based on the rename would just make it easier to work with but can be committed?
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Oct 17, 2011
I have a USB device which creates a Virtual Serial Port on Windows. I am using VB.Net to write and read from the port. My device responds with specific sized set of bytes, but I am finding that SerialPort.Read(byte-array,offset,number-bytes) does not return the full number-bytes but it also does not timeout or generate an exception. Repeated calls return additional fragments (up to 3 calls required). Python code using pySerial does not have the same problem.So, what am I doing wrong here? Am I expecting too much?
Some scenarios are:I write a command to the port and expect to get 4 bytes in response. I get 1 byte first and then 3 bytes on the subsequent call.I write a command and expect 21120 bytes in response. I get 1, 12671 and then 8448 bytes in 3 calls to read from the port.
Here are some excerpts from my code:
Private Sub SetupVirtualSerialPort()
Dim portName As String = "COM" + (m_DeviceContext * -1).ToString
Const baud As Int32 = 9600 '7680000
Const parity As Parity = parity.None
[code]....
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Aug 17, 2009
I'm trying to make a simple Class that reads data from a SerialPort.The Device returns a number of lines of Strings.[code]However running this code in a Form with one TextBox Control (txtLog) Allways results in the "The operation has timed-out." Exception.[code]
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Nov 18, 2010
For whatever odd reason, we have a legacy data recorder device that runs at 9600 baud. Except when it needs to transfer its recorded data to a PC, in which case it switches to 57600 baud.
The old VB6 code worked, although it had its own set of problems of course.
The routine is this: Do several COMMAND/RESPONSE routines to populate a list of available records, listed by timestamp, at 9600 baud. Once a timestamp or several are selected, display a file save dialog. At the moment that dialog is closed, send a command to the device to tell it "hey we're going to warp", sleep for 100ms, then set the baud rate property of the persistent COM1 connection to 57600, before beginning to process XMODEM data and do the progress bar dance.
The problem I'm having is that it doesn't appear that the data received is ever really kosher as far as the byte marshaling is concerned. Which makes me wonder just how well SerialPort is at dynamically changing bauds on the fly. The VB6 version used MSComm.
I've even attempted to just use MSComm through the compatibility layer but "CTL_E is not supported" which makes it sound like it's incapable of doing XMODEM. (?)
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May 9, 2010
A function of my app is to encrypt a file with TripleDES. The problem is that when the app reads the data, encrypts it, and writes it back, the new data is appended. I need it to overwrite the original contents.Here is the code:
Dim
DES As
New
System.Security.Cryptography.TripleDESCryptoServiceProvider[code]............
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Jan 28, 2009
I have a hardware which sends out packets containing 17 bytes to the comport in bursts of 3. the little test VB that I have written receives and displays the bytes in a line of 17 bytes long and works fine until it gets to around 170th packet, then it starts to mix up (looks like shifting the data left) the bytes shift mostly by one digit sometimes by two. then it will continue to give almost a packet correct and a packet shifted for about 50 packets. Then it will correct itself for a long while, but then the speed at which it receives drops. All the packets are sent 3 times, and before things go wrong (within the first 170 packets) the packet counter shows that it receives 3 packet each time but after the problem it goes to 2 packet per burst and then to one.
If i close my VB monitoring program say at packet 165 and immediately open it again, it wont go wrong for another 170 packets, this points the finger at VB. I have check my hardware, there is no problem with that.The program reads port - waits for 17 bytes - once 17 has been received it will go and buffer the packet in an array. In fact they are 2 arrays but printing fro either results in the same problem.I have tried whatever i could think of but to no avail, i am wondering if some kind of house keeping needs to be done to clear something... I am sorry the program is a bit messy but I have been making many changes to find out what the problem is - my code below:[code]
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May 7, 2012
I'm writing an application; I have an Advanced Tree control and a ListBox control. When I populate the ListBox programmatically, using a function that returns a ListBoxItem, it adds the field fine, but displaying incorrectly; it doesn't just add say "My item," it adds "ListViewItem: {My item}"
When I add the item using just a string, it adds fine but I need to use the return function to set the tag data and such, but when I use that function, it adds the above which is really annoying.
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Oct 16, 2009
Let me explain the functions and what they do first.This function writes a key to a specified file:
Public Shared Sub WriteDatabaseKey(ByVal section As String, ByVal keyname As String, ByVal entrystring As String, ByVal filename As String, ByVal filepath As String)
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Jan 7, 2011
I am using:
VB
My.Computer.FileSystem.WriteAllText("J: est.txt", "Text here", True)
to write text files and such. How would I do quotations in that text..say if I wanted to put in
Text Text "More Text" Text.for it to write.
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Feb 21, 2009
Im trying to buffer data being written to a device on a com port. The equipment attached to it does not use any form of flow contol and if you write to much information to quickly it falls over. So I have had the following thoughts.
I would create a list of strings and when I wanted to write data to the com Port I would just add the string to the list. I would then have a Sub running its own thread to step through the list, write the string to the com port ,pause a fixed amount of time, remove string from list and repeat until the list is empty. Then keep looping the above.
Code I have so far is below
Private MsgList as new List (of string)
Private sub MsgPump ()
Do
[Code]....
THis does work but If I add strings to MsgList to quickly it throws an exception.
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Oct 30, 2011
I want to create a tiny program that writes itself. VB.
Basically, I start it off with the smallest coding possible. Then, I want it to be able to automatically generate buttons, forms, labels by itself. I want it to compile another version of itself, and to test if it worked. I want it to in someway to be able to ask the new application if it works, and if it does to close both and to run the newer variation, then to repeat this process. I guess this is kind of like a self-manifesting application that keeps growing; an AI perhaps. Is this possible?
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Sep 30, 2009
I am needing to write to a "rtf" file, and always insert my text on line 3 of either a new or an existing rtf document.I'm familiar with vb, but have not done much with the system.io functions. I have been testing several examples from the internet using the streamreader and streamwriter but still having issues finding a way to "insert text" on a specified line number. My questions:
1)I will always need to write on line #3, do I need to read all lines as this example shows "lines.AddRange(System.IO.File.ReadAllLines("C :/test/myrtffile.rtf"))"
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Mar 19, 2012
i have this message program that writes text to a .txt file when i push a button and a filesystemwatcher that checks for when that file is changed and when it is it set the text of another textbox in my program to the text of the file. in the text i transport over there are usernames, i want the program to check to see if textbox contains that text then i want it to highlight or color or change the font of that text, or username. but i want it to just change the username's attributes not the whole text box,
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Sep 22, 2011
trying to write to c:windowssystem32 on a windows 7 x64 machine, but the application keeps writing to c:windowssyswow64 instead. I have heard of windows interpreting commands and modifying them to be what microsoft "thinks" you are trying to do.when dealing with 32 bit apps running on a 64 bit os.the line of code im using is:
System.IO.File.WriteAllBytes("C:WindowsSystem32dbcon9x64TEST.dll", My.Resources.dbcon9X64)
the issue is I need to write files to both c:windowssystem32 and c:windowssyswow64 ....the files need to have the same name.
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Feb 3, 2012
My application writes to the event log if there is an error or other status updates.
The application checks to see if there is an event source named "applicationName"and if not, it creates the source (see code below).
This works fine if the user is an administrator.
If the user is not an administrator, an error is thrown when SourceExists is called:
{"The source was not found, but some or all event logs could not be searched. Inaccessible logs: Security."}
In my environment, the typical user is NOT an admin. Therefore, I cannot use the event log in my application.
Is there a way around this, or is the event log effectively useless for distributed applications?
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Sep 13, 2011
I want to develop a text editor for writes articles and I want that the user can add hyperlink on any text. How can I do this?
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Mar 23, 2010
Im currently looking fora solution to load/delete/write to a csv file. I tried to save my .txt into .csv but when its loaded into excel it writes everything in column
A1: John Freeman,Apartment 1 Street 2,New York with commas...
I want to put it in column A1: John Freeman B1: Apartment 1 Street 2 C1: New York
What am I missing? This cvs seems like the thing i want to work with.I testet it with writing my user registration form to .csv and its writing it perfectly into excel when i use & vbCrLf & between the text inputs, but will be listing them vertical and not horizontal as i want them to be.Also i don't know how to clear my csv document now and how to call the csv file to a table or a textbox like i did with my .txt file.
[code]...
readalltext can't read .csv so the code should be like?
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May 25, 2007
I have a program that currently takes data and writes it to a MS Excel spreadsheet. (automatically opens the program, creates the cells, and fills them with data)
I would like to add an additional feature to my program that offers support for OpenOffice.org's 'Calc' spreadsheet program. (so users without MS Excel can use the application) So I am basically asking if anyone knows how to automate OpenOffice 'Calc' from VB.net. (I am using Visual Studio 2005)
I have searched on the OpenOffice forums but no one seems to know the vb.net code for this. So I was wondering if anyone here has done this, or would know how to do this.
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Jul 4, 2010
how can I let VB.Net writes an excel 2007 file? For example, the data in a TextBox will be written to the excel file every 30 seconds.The enviroment is VS2008, .Net 3.5.I've just started VB for one month, so please give me a piece of code to help me understand. I tried to find the solution on the Internet, but none of the codes worked for me, some people mentioned import "Microsoft.Office.Interop" in the code, but if do that in my code, VS said that "Namespace or type in the Imports 'Microsoft.Office.Interop' doesn't contain any public member or cannot be found. Make sure the namespace or the type is defined and contains at least one public member. Make sure the imported element name doesn't use any aliases."
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Oct 21, 2010
I have a program which records the phone numbers I dial into one program into its own textbox. But whenever I use numlock to type the phone numbers in, it appears as "abc, etc" in the recording program.
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Sep 17, 2009
why the xmlwirter writes an extra "?" at the begining of the xml. [code] And this is the output. Note the red "?" at the beginning of the xml. Upon close examination, it's a Chr(239) but in console application, it is shown as the "?" [code]
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Dec 13, 2010
Can I Change the location where webbrowser1 read/writes cookies?
Possibly to a resource folder in my form? or a folder on my computer?
Then what should I put in "form closing" to make it delete all the cookies in this folder or location?
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Aug 31, 2010
I was just wondering if it's possible to create an app that interacts with a database hosted on a web server... or is it only possible using VB.NET? Also if it is possible, is there any good documentation or tutorials I could reference?
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Aug 26, 2010
I need to create/get a simple program that opens up a webpage, writes to a log if it is successful or not, logs out and repeats 5 minutes later.I'm not a coder myself, and I have no coders available at my work, I do on the otherhand have access to Visual Basic .NET 2010.
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Aug 26, 2011
I am having a heck of a time with some very simple json. I have a very basic VB.NET webform which which writes out the contents of a datatable serizlized with JavaScriptSerializer.
CODE:
On the jquery side I am doing this.
CODE:
This is returning "invalid json"
Here is the output
CODE:
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