Handler For Memory Form And Listbox?
Jan 20, 2010
I create form with listbox that have data and show new memory form when radiobutton selected . All this work perfect fine, but not code in AddHandler for listbox SelectedIndexChanged . In procedure of addhandler, I see error "name 'lbox' not defined" when I try set global variable to SelectedItem . Code I use I show for you below . Why not this work ?
Private Sub RadioButton4_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles RadioButton4.CheckedChanged
Dim f As New Form 'Create a new Form
Dim lbox As New ListBox 'Create a new ListBox
[code]....
why I have error of not defined "lbox"?
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May 7, 2012
it is clear that an Object handling an event has to unregister himself of that event before it ends, to avoid not been cleared from the memory by the CG - especially when it lives longer than the "Event Raiser" object. But, on the other hand, I wonder if it is possible to encounter this problem on the web server... Is it possible that the server will keep this object alive, even if the execution context (i.e. the web session) has died? Are'nt all the objects related to a session cleared with the session itself?
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Jan 24, 2012
I am passing some values from a Gridview Update Click event to a popup ASP.net page that dynamically builds a series of textboxes in a Placeholder based on the number of sentences that are found in a specific cell of the Grid Row selected.The boxes that are built represent each sentence found in the cell of the selected row. Each sentence is presented for translation, where user enters data into a 2nd dynamically generated textbox.This all works great.Now I have a Listbox beside the 2nd textbox, which sometimes has 1 or more variables that need to placed into the translated sentence. I have set up a Hover menu over the listbox so that I can select the variable and insert it at the end of the sentence in the 2nd textbox. My problem is generating the click event on the dynamically created Listbox. Something like....
Protected Sub ListBox1_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles ListBox1.SelectedIndexChanged
TextBox1.Text = TextBox1.Text & ListBox1.SelectedValue
[code]....
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Aug 3, 2010
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"
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Apr 27, 2010
I have a multiple form application with a listbox on each form. I want to be able to select an item in one listbox on one form and then click a button and it show up in a listbox on another form.
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Apr 12, 2011
I have the current code:Public Declare Function FindWindow Lib "user32.dll" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long
<DllImport("user32.dll", SetLastError:=True, CharSet:=CharSet.Auto)> _
Private Shared Function SendMessage(ByVal hWnd As HandleRef, ByVal Msg As UInteger, ByVal wParam As IntPtr, ByVal lParam As String) As
[code].....
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Feb 23, 2009
I have a form that is built and loaded dynamically when File/open is selected.however I now want to use the same code to open a default file and populate the form using the Form load event to call:
Private Sub OpenToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles OpenToolStripMenuItem.Click how would I do this? Just incase this doesn't make sense, I want the same code to run during form load as if the user selected file/open but do not know the syntax of how to call OpenToolStripMenuItem_Click() from form load.
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Jun 18, 2009
I've got a form with a TabControl. PictureBoxes (containing thumbnails) are added to each TabPage thru a loop. A click event Handler is added for each PictureBox. When a PictureBox is clicked, a new form is created thru code and a PictureBox is added to it that shows the pictures enlarged. What I need is to add another Handler to the PictureBox in the code-generated form so that I can rotate the pictures because some of them (photographs) were taken with the camera at 90 degree angles from vertical. I've tried to come up with a solution but I always run into the problem of the PictureBox on the code-generated form needing to be declared WithEvents before a Handler can be added.
Code for adding PictureBoxes to TabControl:
'Variable p declared public withevents at class level
p = New PictureBox
img = Image.FromFile(Path.GetFullPath(picfile))
[Code].....
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Apr 16, 2011
I have a Windows form in VS2010 with a rectangular area that I draw in with Graphics.DrawImage for best performance. I want to create a Mouse-move event handler just for that area (to change the cursor when the mouse is inside it), along the lines of handlers for the other controls on the form. But since the rectangle isn't a PictureBox or Panel or other control, I don't see an obvious way to handle it. A mouse-move event handler for the entire form could affect the performance of the app.
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Dec 6, 2009
I have a simple, but important question: How can I raise events of my form1 on another module/form?My form tempalte is crowded with events (50 of them contextmenustrip events)How can I place those events on another form/module to clean it up a little?
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Oct 24, 2009
I have a windows application that has a tab control with 5 different tabs. Each of these tabs has a datagrid view that is populated with data on form load with data from SQL Server. I have an event handler for the datagrids for CellValueChanged that appends an asterisk, "*" to the tab, when a change is made, this is meant to mimic the same behavior in VS or SSMS. The issue that I have just realized is that on page load as the datagrids are populated this event handler is raised thousand of times. I have included an If Then statement to exit the sub if it occurs during page load, but am concerned about the performance implications, if any. Is there a better way to handle such functionality? Possibly a way to ignore the event handler on form load? If not is there a negative impact leaving this functionality in?
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Sep 20, 2011
what it does iswhen a user checks an item in the checked list box it transfer it to a listboxso i have a checked list box and a listboxi am planning to put another listboxwhat i would like to be able to do is thatwhen the user checks an item on the checked list box it will transfer the item into the listbox [like the one on my previous thread]and be able to show an messagebox with a textbox [ i read its called an input box ] or another form with a textbox and/or combo box will pop up
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Aug 28, 2009
currently i have a tab control. i want to make a task bar like program to tell me how much each tab is using as if each tab was its own form
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Jul 1, 2009
i have two forms : Form1 and Form2..when i start application form 1 opens up, the memory usage is 10MB then i open form 2 and close form 1, the memory usage is 25MB.Again i close form2 and open form1, then the memory usage is 30MB.Why is this so that form 1 has different memory usage at different times...?
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Oct 4, 2011
When a sub runs, it is using up large chunks of memory on every pass. It is loading pics into a listview. The pics are 1 to 2mb each and it is consuming 30-60mb for each one. How to release the memory once I close the form. Is there anything I can do to reduce it?
Private Sub PhotoFrm_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
For Each ImageStr As String In Images
Dim Extension As String = IO.Path.GetExtension(ImageStr)
Dim fs As New IO.FileStream(ImageStr, IO.FileMode.Open)
Dim br As New IO.BinaryReader(fs)
[Code] .....
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Jun 14, 2011
I am a project analyst emrpesa software and recently in our systems. Net that are still
a minority began to System.OutOfMemoryException.
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Sep 17, 2010
how can i release a form from memory i am using public variables in my form , & the same variables are appearing on the form controls , like text box and datagridview values
i want to use
MyForm = nothing OR MyForm.dispose
so that the form will take rebirth on next open
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Jan 21, 2010
I have many forms in my project. When the project starts to run, the form named as˜frmMawill be loaded. I had given links to load other forms from this form. When other form gets loaded I want to close this main form. To do so I used the following
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May 8, 2012
When I double click on a form control while in the design view in a Web Application project within Visual Studio 2010, say a 'button' or a 'submit' for example, it inserts a javascript function into my .aspx file. When I do this at work it automatically creates an event handler for the control in the code-behind.How do I change this to that setting?I don't want to type those event handler subroutines every time!
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Nov 5, 2009
In 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.
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May 22, 2007
Im 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?
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Nov 24, 2011
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]......................
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Feb 1, 2009
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.
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Jan 20, 2010
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?
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Apr 17, 2011
I'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.
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May 27, 2009
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.
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Jan 11, 2012
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]......
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Feb 9, 2011
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!
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Jun 8, 2010
I wanna to load a web page and login.I know how to do this with a web browser control but:I wanna to create the control runtime and in the memory and not showing anything in the form.I wanna to load many pages in the memory and extract my information needed without anything to see by user.
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Mar 11, 2010
I did a project (College Management) in vb.net 2008 which contains 13 forms in it. I designed the different functions in a different normal form, i.e. frmAdmission, frmSearch etc. When the project run's the main form is loaded. When user chooses a particular function say 'frmSearch' then the main form is unloaded and the form frmSearch is loaded. Now my lecturer told me to use MDI forms instead of normal forms because, normal forms takes larger memory than the MDI forms.
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