Comport Reads Errors After Number Of Good Reads
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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Jul 23, 2010
I'm writing an application in vb.net 2005. The app reads a spreadsheet into a DataSet with ADO.NET and uses a column of that table to populate a ListBox. When a ListBox Item is selected, the user will be presented with detailed information on the selected record.One part of this information isn't in the DataSet. I have to compare a column from the spreadsheet with several external data sources to determine the nature of the record in question. Here's where I have my problem.This comparison has to search through 9.5m rows in a SQL table at one stage. I've checked and there's no way to "shrink" the query down as I'm already only searching absolutely essential data.What happens is that the application never visibly does anything. The CPU usage shoots up to 100% regardless of what it was at beforehand and the system's performance becomes almost unbearably slow.Can anyone suggest a way I can improve this situation while this massive query is running? I was originally going to write the contents of the 9.5m rows in the database table to a text file which I'd then read from, but after 6.5m rows, I got an OutOfMemoryException.
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Mar 29, 2012
i have to create something that uses OpenFileDialog, and reads textfiles that i created it.
i did this
Private Sub SK_btn_OpenFile_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles SK_btn_OpenFile.Click
SK_OpenFileDialog1.ShowDialog()
End Sub
I know how to read the File name, but i want to post the texts that are in the TextFile in my textbox when i press Open/Display file.
Private Sub OpenFileDialog1_FileOk(ByVal sender As System.Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles SK_OpenFileDialog1.FileOk
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Apr 5, 2009
how to make a program that reads the url of ie or Firefox.. really Want to make a program like this ..
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Oct 3, 2011
I would like to query a string that only reads a last character.
sqlstmt = "select * from table where Area like'%A'"
Dim cmd4 As New SqlCommand(sqlstmt, con2)
da = New SqlDataAdapter(cmd4)
ds = New DataSet
[code].....
I have the above codes but i've got '-1' if nothing to read..
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Jun 6, 2011
I used the same exact simple loop to read all the tags on a different xml doc in the same program, but when i put it into this function (litterally a copy and paste and changed filepaths/node names) it only reads the first node, and doesn't go the others.
Private Function ReadKeyXML()
Try
' Algorithm
[code].....
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Jun 21, 2010
This is my 50th attempt to read the memory and probably my last attempt if I don't succeed now T_T I've been trying to write a class that reads from the memory, simply by creating wrappers around the Win32 APIs but I just can't get it to work.
This is how I currently am trying to read the memory from calc.exe:
Public Function ReadMemory(ByVal hProcess As IntPtr, ByVal lpBaseAddress As IntPtr, ByVal nSize As Integer, ByVal lpNumberOfBytesRead As Integer) As String
Dim tmpBuff As Single = 0
[Code]...
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Apr 24, 2010
I've managed to add a media player that reads items from a combobox. Only problem is the next and previous buttons on the media players dont work. I know they work for a LISTEBOX but how to make it work for a COMBOBOX? what code do i need to make it play the next song in the list or the previous song in the list. The name of the combobox is combobox2.
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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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Jun 24, 2010
I've got an application that reads a XML file via a stream reader. The problem is I can't edit my XML file and save it when others are using the application that is using the XML file at the time. how can i get around this?
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Apr 3, 2011
I need to create an application that reads numbers from a file. it then should display the total of the numbers, display the average of the numbers, display the highest number in the file and display the lowest number in the file. We are using visual basic 2008. I am new to this and stuck . How do I begin. I included the number set that we are supposed to read from.
Attached File(s) NumberSet.txt (990bytes)Number of downloads: 80
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Mar 24, 2010
I have successfully gotten the filestream function to read a text file and return bytes. I want it to return letters, not bytes, using random access.
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Sep 12, 2011
We have a reporting app thats needs to update it's charts as the data gets written to it's corresponding table. (the report is based off just one table). Currently we just keep the last read sessionid + rowid (unique combo) in memory and a polling timer just does a select where rowid > what we have in memory (to get the latest rows added). Timer runs every second or so and the fast sql reader does it's job well. So far so good. However I feel this is not optimal because sometimes there are pauses in the data writes due to the process by design. (user clicking the pause button on the system that writes data). Meanwhile our timer keeps hitting the db and does not get any new rows. No errors or anything. How is this situation normally handled. The app that writes the data is separate from the reporting app. The 2 apps run on different machines. Bottomline : How to get data into a c# app as and when it is written into a sql server table without polling unnecessarily.
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Jul 7, 2009
The code below reads each line from a file and if the conditions become true it adds the contents of the file from the particular line and after into a string collection (i.e. the All contents). This is what at least what the code should do as the current one only adds the line that it encounters into the string collection.
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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:
[Code]...
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Jun 11, 2010
What I do is I have a variable on form1 and its an integer which has a value on load of 0 and named count.When I click the 'doSomething' button it is increased by 1 and when I use the function 'msgBox' I get to see 1.After that I start a thread which is going to look up count but when I check the value there is 0.
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Jul 20, 2011
I am writing a windows service that will read records from one table and write them to another table. Problem is when i declare cmd = New SqlCommand(l_sSQL) the code stop executing but the service will still be running. I can insert into the other table using the service but i cant read from the other table.
Code Sample:
Private Sub dbcon()
Dim con As New SqlConnection
Dim cmd As New SqlCommand
Dim adapter As New SqlDataAdapter
[code]...
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Dec 20, 2011
I am trying to write a basic .net program that reads from one file with streamreader, scans each line for specific errors in formating and if the errors exist correct them in an output to another file that I've just renamed as same file name.cache.
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Feb 2, 2009
Is there a way to rotate a label such that it reads vertically? I've checked all of the label properties but there doesn't seem to be one that will do the trick.
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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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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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Jul 15, 2010
My application reads information from an Excel spreadsheet into a DataSet (ds1) which is then filtered into another DataSet (ds2) based on user-specified criteria. The information is basically telephone call logs that reflects when a phone call was made,what extension it was made one, how long the call was, what number was called, etc.When the user's "search" criteria is matched in ds1 above, the application adds the number called to a ListBox on the form. When the ListBox Item is selected, additional information (call duration and such) is displayed to the right of the ListBox. My problem is that a single phone number could have been called multiple times on an extension within the date range the user specifies and for each occurrence of that number in the ListBox, the "expanded" info only reflects the information for the 1st call to that number listed in the DataSet.
The only unique identifier I have is the DateTime field for the row (as this goes up to the second). I thought about putting it into the ListBox item, but I'd prefer that this date not be visible until the user selects the ListBox item to view the details for that call. [code]
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Aug 14, 2009
I want to develop a small application that reads in scanned barcodes into a database table - Would a vb.net form based application that connects to the database be best approach? What I'm think is each time the user scans in the barcode - a message appears on the form saying the barcode that has been scanned.
1.Would I need to program anything within the program to check whether the barcode scanner is connected (or is this not necessary since it works like a keyboard device?)
2. How could I automate the scanning in without requiring any user intervention like a button which saves it to the database - so basically as soon as a barcode is scanned in - it is saved to the database and the next barcode can be scanned in etc.
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May 10, 2009
I'm trying to create a program which reads a text file into an array.
[Code]...
But that's just silly so how can I fix this? Lines isn't being assigned a null value it's being assigned the first line of text in the file which has text in it so I'm confused.
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Dec 31, 2007
I am working on a project that involes reading an Excel file, picking through it, then creating a flat CSV file. One of the the data elements I am picking up is a 9 character string that may be numeric, or contain one or more alpha chatacters. Excel has a nasty habit of converting long numerics to scientific notaion. I can overcome this by converting the "general" string to "TEXT".
However, there is one instance where I can not get the function to work...the string is "90333E108" ( the CUSIP for USU). Regardless, the text string is saved properly into the CSV file. When opened in a text editor, it reads correctly.
When opened with Excel, it is in scientific notation. Changing the field to "text" from "scientific" still displays "9.03E+112".
how to create an csv file that Excel will open and read correctly?
You can test this by creating an Excel workbook, format all cells as TEXT and add the following data:
90333E108
123
2
[Code]....
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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.
[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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Apr 4, 2011
I am using VS2008(VB.NET) and SQL Server2000. I want to make an application which reads files and Insert Data into SQL. If first file has some error. Write into log and Move Next file for Proceed. How can I do that.
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Jul 1, 2010
im makign a game that reads text files off of an ftp server. everything is working great. except for the fact that i cant read more then the first line of the players text file. how would i use substring to, for example, look for 'inventory' and get all the info under 'inventory' and above the next title?
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Jan 4, 2010
I have a piece of code that reads in lines of tabbed text. It is a game of who wants to be a millionaire. What I would like to do is get the game to incorporate random questioning.
The format of the text file is as follows:
Which record company did the Beatles create? (tab)Apple Records (tab)Sony (tab)BMG (tab)LiteFM (tab)Apple Records (tab) Which has the highest mountain? (tab)Mars (tab)Ireland (tab)Iceland (tab)America (tab)Mars(tab) With a set amount of lines. I want the program to choose each question randomly and not to repeat the question. I'm not sure how to incorporate it into the code.
Quote:
[CODE].....................
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