does visual basic have any function to allocate a memory by specfying the size of it? I just want to experiment with it, like see what happens when i allocate 2GB of memory on my p3 MHz 512MB ram box =) I know obviously it will crash or have high page file access.
View 8 RepliesI have resorted to using the Win32 API calls VirtualAlloc/VirtualFree to allocate and release memory blocks greater than 2GB in size.
I should be able to use the AllocHGlobal function from the System.Runtime.InteropServices.Marshal class to do the same.
However, the following code gives an arithmetic overflow exception (note the explicit cast to long which should instance a 64 bit pointer).
Dim p As IntPtr = System.Runtime.InteropServices.Marshal.AllocHGlobal(New IntPtr(CLng(3221225472)))
System.Runtime.InteropServices.Marshal.FreeHGlobal(p)
So my question is, Can I use AllocHGlobal to allocate more than 2GB of memory?
I have a program in C++, that is doing some calculations. I use a vector in C++ and resize the vector in the program, in order to conserve and allocate memory. Can you allocate memory in vb.net? So if my user inputs 1000, I want an array/vector to have a size of 1000. Can I change the size of the vector in the program? And is there a difference between container types in vb.net, I was just assuming
Dim xx(1 to 1000) as double, is the standard way of declaring.
And resize xx(1 to N) would be the way to resize.
I am using visual studio 2008 express.
Once i allocate arrays is the memory allocated for them immediatlyy or once i add data to the array? like say i create an integer with 400 million arrays (lol) would visual basic allocate memory immediately for each of the 400 million arrays or once there is data allocated to one of the 400 million arrays, say when i put the number 4 in the 100th array.
View 1 RepliesIs there any way we could get directly say the 1000 characters after the first 5000 characters, skipping everything before that after sending in an HTTP request to an HTTPS page using either GET or POST in VB.NET? The reason why I ask this question is because in one of the webpage I am trying the get through my program, the website is sending response data in chunks with the first chunk containing some javascript garbage that I have no interest in, the only data I care is in the second chunk and
how to get the second chunk after receiving the first one since it is within the same HTTP request.It would save some time and Internet traffic if I can skip the first chunk that I do not need.Is that possible or I am just day dreaming?
ADDED: Here is how a typical header of the response I am getting from the webpage I am trying to get:
Date: Mon, 20 Jun 2011 13:21:56 GMT
Set-Cookie: JSESSIONID=1AF1AF9EF936E1CB2FA85B750EDC67C4; Path=****some path******; Secure
Content-Type: text/html; charset=ISO-8859-1[code].....
Not sure if that helps, but as you can see, the chunk size is not visible to me, there is no "Trailer" in the header as well.
read each chunk of 256 bytes from a 32k file and then add the total value of each byte's decimal value. This will be some huge number which then needs to be converted to hex (Hex(number)and then truncate down to the LSB (I.E. 7F{4B}) and then convert the truncated byte (4B) back to a decimal (Num = Val("&H" & Num).
View 2 RepliesSay I have a 5 GB file. I want to split it in the following way.
First 100 MB is on the file
The rest go some reserve file
I do not want to use readalllines kind of function because it's too slow for large files.
I do not want to read the whole file to the memory. I want the program to handle only a medium chunk of data at a time.
I am trying to connect to an online database using the following code:
Imports System.IO
Imports System.Data.SqlClient
Public Class frmMain
[Code]....
It gives me the following error:
Could not allocate a new page for database 'databasename' because of insufficient disk space in filegroup 'PRIMARY'. Create the necessary space by dropping objects in the filegroup, adding additional files to the filegroup, or setting autogrowth on for existing files in the filegroup.
I am currently trying to allocate a number of group boxes dynamically. Previously (in other languages) when I have carried out something like this I have used the '&' to substitute the contents of the variable direct into the code I.E
For I = 1 to 20
Groupboxname = "GroupBox"+I
Weatherstates.&groupbox.controlls.add(obutton)
next
This would then have the result of creating a button in all the group boxes, however this does not appear to work in VB .net 2010
I have looked at Directcast, but i am a even more confused. Is there a simple way to substitute the contents of a variable into the code ?
A friend and I are working on a project where we're required to build a reliable UDPclient/server using VB.Net. We have things working well, but one thing that still eludes us is how to dynamically allocate a (byte) buffer for the incoming data. Right now we have to hard code a maximum value/MTU (or use a really large buffer size and resize it once we've finished receiving). Does anyone know of a way that this can be done without needing to specify the receive buffer size?
Basically, before calling the receive function on the socket with a buffer of size x, we want to know x so we can allocate an appropriately sized buffer. Perhaps this is a problem in all socket programing that you just have to deal with??
I have six textboxes, and upon button press it randomly generates six numbers, one in eact text box e.g. [43] [85] [93] [1] [0] [17]..i create another six textboxes and at the same time allocate these numbers in ascending/descending numbers.I am not looking for any codes whatsoever, as i love the challenge of VB.Net.
View 2 RepliesIn VB 2005, I am calling a C++ DLL function that returns the address in memory and size in bytes of a jpeg image. How can I load that jpeg image directly from memory into a picture box in my VB form? I cannot afford to save it to disk first.
View 10 RepliesIm getting a problem with one of my programs I have made in visual basic.NET where it gives me a memory error when i debug the program in the IDE. the exact error is this: "Attempted to read or write protected memory. This is often an indication that other memory is corrupt". My program basically has a few forms with text fields on that get their text values from an access database on the same hard drive. Im wondering if im doing something wrong because my program just seems to eat up memory whenever it does anything. For example I have one form that has a combobox on it and when you change the drop down list selection it retreives a few strings from the database and puts them into the relevant text boxes, if you keep changing the selection then the memory usage (in task manager) just keeps going up and up. occasionally I get the error mentioned above when debugging but in my built version of the program it throws an exception everytime the memory usage gets past 49K.
Also I noticed when debugging in the "immediate window" frame I get the following message often:A first chance exception of type 'System. Invalid OperationException' occurred in System.Data.dll...Do I need to somehow be "releasing" the memory that is used to gather data once it becomes redundant?
I am using the following code
This error occurs :
Attempted to read or write protected memory. This is often an indication that other memory is corrupt.
Attempted to read or write protected memory. This is often an indication that other memory is corrupt.
Public Class FormRegEnumValue
[CODE]......................
QuoteSystem.AccessViolationException was unhandled Message="Attempted to read or write protected memory. This is often an indication that other memory is corrupt." Source="System.Windows.Forms"
Im designing a web browser and i continue to receive this error after going to about 3 websites it crashes with that error.
I have a BackgroundWorker object that I instantiated to perform a DB process on a background thread ansynchronously. I have event handlers for DoWork and RunWorkerCompleted. I can tell that the BackgroundWorker is disposing of itself because I added a message box into the Disposed event handler.Is it necessary to detach the event handlers to ensure that the memory is cleaned up and that there are not memory leaks?
View 1 RepliesI've noticed that every time I start a new thread in my program, the memory usage jumps about 1000k and it never goes back down. I have ensured that the thread is no longer running, and only one instance of my worker thread is ever running at a time. I am using ThreadPool.QueueUserWorkItem and ASyncOperation to get stuff done. The program starts using a Sub Main in a module that uses STAThread; I read that using STAThread instead of MTAThread makes it impossible for the Garbage Collector to get in and consider objects for garbage collection. However, when I change the STAThread to an MTAThread, the WebBrowser control in my frmMain cannot be instantiated.
I get this exception:
Code: An unhandled exception of type 'System.Threading.ThreadStateException' occurred in System.Windows.Forms.dll
Additional information: ActiveX control '8856f961-340a-11d0-a96b-00c04fd705a2' cannot be instantiated because the current thread is not in a single-threaded apartment. I do threading with the WebBrowser control, so will using MTAThread fix my problem? If so, how should I partition my code so that the WebBrowser control won't be affected by the above exception? I call the thread repeatedly with a timer (although only one instance ever runs at a time), and my program's memory usage starts at about 5000k and can jump to 300,000k+ depending on many times the thread needs to be called.
I cannot use Visual Basic 2008 at all. When I go to "new project" and choose "Windows Form Application" I get this error.I have tried multiple uninstall/reinstall with no result.A microsoft reply to this suggested that I needed: " .NET Framework 2.0 Service Pack 1 " I checked, and I did not have the .netframework 2.0 service Pack 1.
When I tried to download and install the above from Microsoft.com, the istaller said that "it was not allowsed" and I was not able to install the service pack 1.
I tried Uninstalling net framework 3.5, 3.0, 2.0 and then reinstalling .netframework 2.0 sevice pack 1; then reinstalling Visual basic 2008 express edition. At the reinstall of Visual basic 2008, .netframework 2.0 sevice pack 1 is unistalled by .net framework service pack 2.When I check the foruims for simiar problems, the formus are mostly for Visual basic 5.0, or other programs that I do not have.
Here is the programs I have installed:
Operating system: Windows XP
Microsoft .net framework 1.1
Microsoft .NET framwork 1.1 Hotfix(KB928366)
Microsoft .Net Framework 2.0 Service Pack 2
[code]....
All the security updates and hotfixes for Widows XP.
The follow code can be called about 6K times on the server it is run on then gets a out of memory error in the last catch statement. I don't see what is wrong with the code, it works well up until the out of memory..
Public Function AddUserToGroup(ByVal sSamAccountName As String, ByVal sGroupName As String) As Boolean
Try
Dim returnStatus As Boolean = True[code]......
I have two forms, Form1 and Form2. Form2 has a button to show OpenFileDialog. I call Form2 from Form1 by a button. My startUp Form is Form1. When i start debugging, i press my Form1's button to show my Form2, it shows, but when i click On Form2's Button to show OpenFileDialog it is giving me exception that
"Attempted to read or write protected memory. This is often an indication that other memory is corrupt."
When i set my startup Form to Form2 and click Form2's Button to show OpenFileDialog then it shows!
I have a new problem with this same Form Printing project and I get exactly the same exception but from the different point of code:
line 538: d.PrintFunction(c, typePrint, mp, x, y, extendedHeight, ScanForChildControls)
The exception type is System.AccessViolationException and it says (after I translate it from my own language in which the message is given in my pc, into English):"Protected memory was tried to be read or written. This often indicates that the other memory is damaged"
I am getting the following error: "Attempted to read or write protected memory. This is often an indication that other memory is corrupt". i am using interop service.
View 2 RepliesThis code was put together for a one time run. It's purpose is to count all the pages in a group of images. After about 6000 of 1,250,000 images in ##X it throws an "out of memory" error. Besides it being thrown together for a one time run does anybody see anything obvious that could be causing the error?
CODE:
I am using VB.NET 2010 and accessing a DLL that was created in VB6.I added the DLL in the References, and in the program I do the following:
Dim
RTF As
myDLL.clsRTF
[code]....
I have the following method for looping through a table, changint some values in every row and saving the chages back to the database. To make things go faster I am fetching data in sets of 10,000 rows. This is a large table with over 25 million records in it.
The problem is that my application doesn't seems to be releasing any memory. I have tried redeclaring the records variable to nothing or explicitly caling the garbage collector but the memory stays there.Runnning the built-in VS10 profiler I can see that the culprit is the system.linq.enumerable.tolist() method which takes up over 98% of my memory. How do I release that memory after the call to saveChanges?
[Code]...
I have a hard problem here: how to cleanup the no use memory from the RAM?
[Code]...
I have a container that need to add many PictureBoxes with a quite large image, then i need to clear all PictureBoxes and create some new ones. like this: If I click the button some more times, my computer will be out of ram, whatever how many ram do your computer have.How can I dispose all the things used in Graphics and the controls in FlowLayoutPanel1 but not disposing the FlowLayoutPanel1 itself?
How can i detect how much memory each tab is using
View 4 Repliesi was concerned if constants take up storage. if a class had 10 integer constants at class level, will that adds up to 40bytes of storage or is that actually not true because they are constants?
what i'm trying to do: find the best place to put the constants that i need to access at class scope, and whether its best to make them shared or not. [constants are private]
A short while ago, I posted the following code snippet in reply to someone who was looking to make a simple encoded password... See here for a full explanation of how this works --> [URL].
[Code]....
What is the best way to get a structure from memory, I know the format:
[Code]...
The structure is 53 bytes until the chat text, the message length is determined by one of the structure variables LineLength, so what is the best way to get that and put into into a structure?