SyncLock On Write - Read - Or Both?
Jan 7, 2011
Suppose I have a byte array, Private Data as Byte(). This array is private within a class. The class provides public functions for reading and writing to Data. This class can be accessed by multiple threads, so I want to avoid a situation where reading from it and writing from it don't happen at the same time.
For now, I am using SyncLock to avoid issues. Can I put SyncLock Data in just the write functions, or does it need to be in the read functions? Or, both? I don't have a specific code example in mind. I am just curious if there is any benefit to locking for both read and write functions if the writing functions' SyncLock will make writing have exclusive access to it in the first place.
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May 7, 2012
I have a folder called movies. In this folder is a collection of different movies each in their own folder with their own xml file called movie.xml.I would like to extract lets say the localtitle and aspectratio from each movie xml and send to Excel. What code would I need to achieve this?So far I have the attached code which reads only one file and it is directly from the xml outside of a folder.
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Jun 13, 2009
Is there anybody out here in the VB, C# 2008 world that can direct me in the right direction? I do not want anything that has todo with c/C++or Direct Draw. When converting, there is no equal for SizeOf, and a few other things. I am using Lame 3.98.2.exe in my app along with LameShell that works fine for resampling, but , not for decoding an mp3 to wav or encoding a wav to mp3. You can find the LameShell project at [URL] . LameShell is a wrapper for the Lame.exe file. Here is the complete LameShell class file along with my app button clicks for the following,
[Code]...
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Dec 21, 2010
I am trying to extend an application to to write the details from textboxes on a invoice form to an xml file.I have created 3 methods for my invoice class which will open the invoice xml document, write to it, and close it.The open Invoice method creates and invoice.xml file and writes a start tag named invoices.
The WriteInvoice method writes an invoice element for the invoice with attribute named customerName and three child elements named ordertotal, discounTotal and Invoice total. These values are taken from the textboxes form the form.
The CloseInvoice writes the end tag for the root element(invoices) and closes the file.
I have wriiten code for these methods but can only get the open invoice method to work.
My code for the 3 methods is shown below:
Public Sub OpenInvoices()
Dim sInvPath As String = "C:MurachBeginning VB.NETExercise startsVB.NETChapter 14InvoiceInvoices.xml"
Dim InvoiceWriter As New XmlTextWriter(sInvPath, Nothing)
InvoiceWriter.Formatting = Formatting.Indented 'Set formatting of XML file
[Code]...
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Feb 15, 2012
I have several programs that must write to HKLM in XP and Windows 7/64 Pro.
The programs work in VB6 but not in VB.Net 2008 on target machines. It does works on our development machine.
Same exact windows. [code]...
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Mar 15, 2010
How to communicate with a USB port using VB.NET?
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Sep 21, 2009
i'm using sharpdevelop to program WPF application(I'm newbie to WPF i've knowledge of VB only and no C#, is it necessary to learn C# to know WPF ?).
and i want to read CSV file first. after that i want to modify and save file. any suggestions and pointers for this ?
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Nov 15, 2009
How do I read, write and delete a registry using VB 2005/2008?
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Jul 30, 2009
recommend some tutorials that show very simple examples on how one can read / rwite to an SQL db?
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Feb 27, 2010
i'm trying to read from a file and copy the text into a 2d array withought the selected item from a list box then rewrite the file from the array into the text file. however it writes a single part of the array times the variable count when i write back to the csv file. within the array everything is correct its only when i rewrite to the file is when the problems occur.
[Code]....
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Nov 9, 2010
I have the following code for reading XML files.[code]...
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Jan 27, 2010
reading and writing files. Let's say I have a text file with multiple lines that I want to be read into my visual basic program. The first line is displayed in textboxA while the rest of the lines are displayed in textboxB. How do I accomplish this? Am I able to use the peek method for textboxB but somehow tell it to skip the first line? Now textboxB is obviously a multiline textbox and I want the user to be able to type something into another textbox (textboxC), press a button, and it will be displayed in textboxA. How do I make the text in textboxC get displayed on the first line of textboxA and move all the other lines down the list?
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May 5, 2009
Imports System.ComponentModel
Imports System.Drawing
Imports System.Windows.Forms
Imports System.IO
[code]....
I want read the content of the text file and write to vb.net application. My text file name is wires.txt. The above code only read and the file appear on the application. I dont want the file to be visible to the end user.
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Dec 29, 2010
i am using VB2008 to develop a Settings program for my game Lined World, creating with Game Maker. I've created a settings.ini:
[screen]
fullscreen=(off or on)
resolution=(800x600 or 1024x768)
[code]....
answers are depending on settings
now, i wanna create in the settings app the following:
"fullscreen" (radiobutton-on & radiobutton-off)
[code]....
if radiobutton fullscreen is on, [screen]fullscreen must be on, and if turned to off, the INI value should be "off".
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Mar 22, 2009
How can I read and write JPG tags using VB6. The ones that I want to read& write are
Title
Subject
Keywords &
Comments.
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Mar 11, 2010
I'm using begintransaction to update multi-tables. I need to update one of the table while retrieving some records from that same table before commit. But it seem the table become locked after I inserted a record, and timeout at last.
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Nov 7, 2009
I'm creating a project where I need to store information in two files. As I understand, I can store information in a text file or a binary file?
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Mar 31, 2009
i need to read and write to a database (access 07) using visual studio coding in vb.
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May 25, 2011
I am struggling with vb.net. I can read from a file but not able to establish a writing object. what I have so far is this.
Imports System
Imports System.IO
Imports System.Text
PublicClass EuroConverter
PrivateSub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
[Code] .....
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Feb 13, 2012
My first question has to do with the opening lines needed in a VB program in order to connect to Excel 2007 and read/write some data from/to it. I know the process only slightly and reading and writing to the cells is not my real concern for the moment. What I need to become familliar with are the lines like this:
CODE:
This is just one of the examples I have read through and to be honest I only follow this slightly. The trouble was that with each new article I read, people did this differently, not the variables on the left mind you, just that some left out lines, which I can see could be done based on circumstances. Still others said the Imports line was not needed....etc...and other loaded up at least 3 or four more Imports lines insisting all were needed.
I'm looking for some straight-forward advice on what is the minimum needed to access an existing Excel spreadhseet and to just read some of it's cells to variables in the code and then writed some data back to certain cells within the spreadsheet and then save and close it.
Also, please note that I am using VB 2010 Express. Why, because I'm a broke developer who spent most of last year out of work. I have a new contract assignment which is so far going well but will go even better if I can master this technique with VB.NET, not VBA. And all the docs I've read said that even though VB 2010 Express is a watered down version of VS, I should be able to do medium level tasks such as this with it.
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Dec 9, 2009
Trying to emulate a typing application that when typing data in a WPF form, the info gets transferred to another application, such as notepad, word, etc. My first attempt involved using the .Sendkeys method but it doesn't seem to be repeatable 100% of the time. I initially had a button that when pressed would transfer data from a WPF app field to an open notepad app. Again, if I pressed it several times in a row, it would be hit or miss. It's like it hangs up and then after enough time, I try again and it works. I really need it to be 100%. Is there a fix for this method or should I take on a different approach? It would be ideal if I could go from notepad, word, etc. back to the WPF form as well, but I thought I would get one way working first.
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May 19, 2010
I have a DB stored on our internal site and I want to read/write this file as it's updated. How do I download the file, then upload it after changes.Here is what I know about the link
Protocol: HyperText Transfer Protocol with Privacy
Type: XML Document
Address: [URL]
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Apr 11, 2009
i had an old oledb connector from a .net 2003 application i tried to follow the same steps i used for that but it wont allow me to edit the access database.i was trying to avoid using sql strings because my database is rather large and the primary use of this db is for data entrys.
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Oct 15, 2009
in the following thread, [URL]..my first reply, writes and reads two files..
my question is, is that code used properly for writing/reading those 2 files?
for some odd reason, i feel like i am over using the writers/readers.is there a way to only use one writer/reader, not 2, as my code in that thread does, to write/read 2 or more files?
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Sep 15, 2010
I was just wondering if mixing SyncLock blocks and Monitor.Enter/Exit statements is dangerous. I know SyncLock uses Monitor and a Try block in the background, but are there any problems with using the two together for thread synchronization?
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Mar 8, 2010
In a multithreaded application. I have a bunch of function that loop through a collection to read the information. I also have a bunch of function that modifies that same collection.
I'm looking for a way to isolate all the read and the write together. I don't want a write to be done while a read is in progress. I was thinking of using SyncLock on the collection object but this will block multiple read trying to work in parallel.
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Jan 3, 2012
I'm looking at an old web app I wrote and it is taking about an hour to read 4500 records from a DataTable so it can write them to a CSV file.
The DataTable contains... 376 columns
At least, I think that's what Excel's NL column converts to. I just looked up the column count now and had no idea there were so many. Our software vendor hasn't realized the value of dynamic sql statements for this process, so every software "upgrade" just keeps adding more columns rather than only selecting the ones needed. I cannot alter the SQL statement that generates the data
Depending on the data type, the data needs to be formatted in a specific format Data does contains special characters, such as commas The slow part is reading the data. Getting the data from the SQL server and writing it to a CSV is fast.
Here's the code. Forgive the mess, I wrote it back when I didn't know what I was doing and when I still was working in VB
Function ReadDataTableForCSV(dt as DataTable)
Dim sb = New StringBuilder()
Dim dataTypes As New Dictionary(Of String, Integer)
[code]....
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Oct 26, 2009
I'm here to ask about read and write to backup tape drives how i can send data or receive it from backup drives
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Aug 4, 2009
I have an application that works in both 32 and 64 bit, except that on the 64 bit system it can not open/ read/write any files.I know the 64bit file system is different, from what I heard. How can I make up for the changes? I have no access to a 64bit system, but I want to make my program able to find and open the files.
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Feb 25, 2009
for starters not sure if this is the right place for the post considering that it includes MySQL and VB, its here.I'm trying to load data from one table into a combo box as the data you can select, this i have been able to do "tbl_Wind" using "WindDirID" and "WindDir"
also, I am trying to select (if it exists) a value from "tbl_date" "WindDirID" to select a value from the existing data in the combo box loaded from "tbl_wind"and finally, I want to be able to change the value in the "tbl_Date" depending on if a value is selected in the combo box.when a new record is created in tbl_date it uses default values, so there is always something in the field.below is about how far i got, and its the only part that works (extracted and edited of course to exclude the other queries)
[Code]...
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