Does Assigning To Nothing Cause Dispose To Be Invoked
Jul 20, 2009
I recently saw some VB .NET code as follows:[code]Does assigning Nothing to service do anything? If it is a garbage collection issue, I am assuming that when "service" went out of scope the referenced object would be garbage collected and the dispose method called on the object.It seems to me that assigning this variable Nothing can't really do anything, as there could be another reference to the object around so the reference counts haev to be checked anyways.
I have a project in which checkedListBox is invoked by web reference .. I have put the groupbox with other controls shown in picture but when i get the files in checkedListBox and click on download I get the error shown in picture below another how to get this top bar in checkedlistbox..
Writing a custom validator for a dropdownlist that is using autopostback. Seems to ignore the validation altogether. Why is it ignored and is there an easy fix? Note I did not use ControlToValidate
For debugging purposes, I want it to fail every time.It doesn't seem to be executing the behind code at all. For debugging, I added the line response.redirect("dummy.html") ... which never gets called, which also indicates (I think) that the validator never gets called.
There is something strange going on in my VB 2005 program that I don't understand.. I have a form that has several tab pages. Each page has one or more DataGridView controls. When a user selects an item on one DataGridView , I want to deselect anything currently selected on any other DataGridView on that tab page. The only thing that should then be selected is the item I clicked on in the current DataGridView .
I created the following code (note there is a CellContentClick handler for each DataGridView control and there are DeselectAll... and RefreshAll... subroutines for each tab page).
It's fairly straightforward. But notice where I placed the XXX NOTE comment below. If I place a breakpoint there, run the program and click on various cells in various grids, and then click on the specified grid cell, I can create situations where the breakpoint is never reached! Thus, I don't turn off the selection in other grids.
How can this be? Is there some setting for DataGridView controls that I've inadvertently set incorrectly (without my listing them all here)? Or is there some bug in VB I'm unaware of? The "DeselectAll" subroutine merely iterates over all DataGridView controls in the current tab page (except for the current DataGridView) and calls ClearSelection on each such grid. RefreshAll calls Refresh on every DataGridView on the current tab page.
I'm making a little program in where i'm trying to invoke a method from a class dynamically with so called Reflection.
The class I'm trying to call is called ContactList and i try to invoke the property in this class called count. The assembly itself is called Contact.Exe
Now I have the following code where I make an instance of the ContactList class in the Contact.exe assembly:
I have a form in Visual Basic that is adding a row of data to an Access Database.What will happen (or rather what I would like to happen) is that when the form is created, a row will be added to said database. Once that row is added, I want to have another form open (called NewWindowA) which will pull information on that database that is related to the ID of the row that was created from the first form.I know that in NewWindowA I need to have the form load the values on Load. But my question is: How do you pass a value to a new window that's invoked by some action?
How do you pass multiple parameters to a Sub which has to be invoked?Again, I've only been coding for about 3 days so please speak as if your trying to teach a child to tie his shoe.
http:[url].... contains a Visual Studio 2010 Solution with a Form and a User Control.
Question. Why isn't OnMouseMove (at top below Constructor) being called with every movement of the mouse across the UserControl's grid?My intention is to have a reticle (crosshairs) replace (override) the existing mouse cursor and show a reticle with x and y coordinates?I have another form upon which a User Control with similar functionality is working perfectly.
I'm trying to manipulate something that is in a different thread, and I know I need to do something by the way of Invoked procedure, but I'm unclear on how. I looked up some examples here on the forums and tried to follow the basic template, but I continue to have the same problem. how to use invoke correctly.
Private Sub getMessage() For Me.infiniteCounter = 1 To 2 'Try
What I am trying to do: There are three powershell scripts with different time delays as shown below.I am trying to run them asynchronously in .NET and I followed this article to implement Asyncrhonous programming. Where I am stuck:The I am not able to retrieve output after the events are invoked.The scripts are being called but then the program ends and it shows "Press any key to continue" in console windows.I don't what I am missing here.
Info: JobRequest is a class that I use to pass around information keep track of jobs.
I have a program, and there is a timer to run it every 15 minutes. Every time it run, it will create a new exe / thread, (I monitor this thru an external software called TCPView). With the thread growing, it may slow down the performance, is there a way to dispose the thread before a new one is created?
Private Sub Processing() Dim tmrThreadingTimer As Threading.Timer Try
I am having fun working with System.Threading.Tasks. Many of the code samples I see, however, look something like so:
Dim lcTask = Task.Factory.StartNew(Sub() DoSomeWork()) Dim lcTaskLong = Task.Factory.StartNew(Sub() DoSomeWork(), TaskCreationOptions.LongRunning) Task.WaitAll(lcTask, lcTaskLong)
That's the extent of the sample.Tasks implement IDisposable, so obviously I'm supposed to dispose of them, but what if I just want to "Fire and Forget"?If I don't dispose, will I leak threads/handles/memory/karma?Am I using tasks "wrong"? (Should just use a delegate and leave tasks alone?)
Can I dispose in a "ContinueWith()"? (That seems like playing Russian Roulette.)[URL]..
When is it appropriate to apply the dispose method to controls?For example in a form that has five group boxes, once the first group box is used to gather user entries and is no longer needed, is it worth it to apply the dispose method to the first group box? Is it needed for local variables, for example a StringBuilder used within a private function which is only used while the function is executing?
I attempting to dispose / close a startup form from a sub. Basically, I using the filesystemwatcher to watch for file creation, if the file is created, run some code and close the form.how to pass in some reference form. Using and new to vs2008. A bit of leap from VB 6.0.
Imports System.IO Public watchfolder As System.IO.FileSystemWatcher Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Hello, I have a WPF Window that I show with Window.Show(). When I click X the form closes. But it is still in memory and the GC never comes and cleans it up. Also I do not have any refrences/handles to it.
I am using the following code with the window:
Code: Public Class PageWindow Implements System.IDisposable Public UserPressedExit As Boolean
I was experimenting with ways to get rid of some memory leaks within my application the other day when I realized that I know virtually nothing about cleaning up my resources. I did some research, and hoped that just calling the .dispose() would solve all of my problems. We have a table in our database that contains about 65,000 records. Obviously when I fill my dataset from the dataadapter, the memory usage can get pretty high. When I called the dispose method on the dataset, I was surprised to find out that NONE of the memory got released.
Out of pure curiosity, is there a way to free the memory used by a StringBuilder, other than the obvious MyBuilder = New StringBuilder and MyBuilder.Remove(0, Length) (although I guess the later wouldn't free anything, would it?)
hi everyone i created a thumbnail dll for my file type my class dll create thumb for my files type but my class no dispose after create thumbnail this is my project : HPTShellExtThumbnailHandler.rar
On the back of a Windows Form, I get a window DC, create a Graphics object with Graphics.FromHdc, and then dispose the Graphics object before releasing the DC.
Private Declare Function GetWindowDC Lib "user32.dll" (ByVal hwnd As IntPtr) As IntPtr Private Declare Function ReleaseDC Lib "user32.dll" (ByVal hwnd As IntPtr, ByVal hdc As IntPtr) As Integer Dim hdc As IntPtr = GetWindowDC(Me.Handle)
[code]....
Why did they do it this way?Should the DC be released before or after Graphics.Dispose?It is possible that the wrong order can cause resource leaks or memory corruption?
When you set a region equal to another, or set it equal to a new instance, do you have to call dispose on the region, or does VB do that? (I guess this isn't necessarily specific to regions)
ex:
'at some point in the code a region is created Dim Rgn as New Region(SomeRect) '....
[Code].....
If Rgn now points to the Rgns(0) clone, what happens to the original memory created by "New Region(SomeRect)"? Do I need to call dispose on Rgn before assigning it to the the Rgns(0) clone?
how do you correctly dispose a shape in vb.net ie when you draw a rectangle using the pen function how do I depose it so that it will disappear from the form, for some reason once its drawn if I draw a new shape it keeps the previous one and just overlays the new one and I use shape.dispose, and pen.dispose?
whats the difference of Me.Close and Me.Dispose...What code does releases memory resources that was used by ".show" command?Im currently creating a program and i just used both of them... is that ok?if it is ok... i know some commands have issues on what should i type first.. so what will i type first?
I Want to know garbage collector works in .net there is something heap and stack funda.so can u please tell me from where i get reference of whole funda of that.and i have another question is that Please see below the code.here i declare one dt and get some data in it.and i don't want that dt after data come in text boxes.so in finally method i do dispose using dt.dispoe().
but after that i write little code to check whether the dt correctly dispose or not.so i check with if condition after disposing.you can check code given below for that condition.as per condition it gives me "Nikunj" Ouput in message box it meanse dt is not disposed after calling the dispose method.so can u please tell me why?And i Want to know about all resources which i used i want to know how can i free it.whether it is variable,object,datatable,datareader etc..... if it is any where with example then please give me link.and if it's from msdn then it's better. i want to know from Microsoft that
I have Overloaded the Dispose method of System.Windows.Forms.Form Class in which I have written some extra code which I need to execute when object of Form Disposes. But when I create the object of Form in 'Using' statement, the 'End Using, statement do not execute my overloaded Dispose method. What should I do?
