How To Check If Mutex Is Released
Dec 23, 2009
i've got a Set and a Get in a property. I want to allow multiple threads to do Get anytime they wish to, however if any thread tries to do Set, all threads must not be able to Get/Set until the Set is complete.[code]the problem is that this is pretty inefficient because each request to Get will steal the Mutex and prevent other Gets until the stolen Mutex is Released. Is there anyway to just check if a Mutex is released instead of using WaitOne because WaitOne checks and gains control of the Mutex which is not what i want
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Oct 26, 2011
I'm trying to implement single instance application using mutex.the application can run only one instance from a given directory.i tried to implement it in Applicationsevents class but it's not working.I replicated it with a test harness with a single form.my ApplicationEvents.vb code:
Private Sub SingleInstanceCheck(ByVal sender As Object, ByVal e As Microsoft.VisualBasic.ApplicationServices.StartupEventArgs) Handles Me.Startup
Dim strLoc As String = Assembly.GetExecutingAssembly().Location
[code]....
it runs multiple instances.Things I am not able change:
1.project setting has "Enable Application framework" ticked
2. ApplicationEvents.vb handles UnhandleException which means i cant have a module as startup.
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Aug 10, 2011
My application is very very speed esential and even a microsecond matters.I am using semaphore(1,1) at varios places. I think it can be easily converted into mutex.But I want to know if it will be advantageous or its one and the same thing as far as speed is concerned.
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Nov 17, 2010
I have a mutex and threaded related question about = Run one or the other per call to routine
[Code]...
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May 4, 2011
Is there a way to do a read-only test of the blocking state of a mutex? Currently I use the return value of WaitOne(0,False). This works fine, provided that if the return is true, I also call ReleaseMutex. Failing to do this, my test would corrupt the state of the mutex. So, the test is effective, but it has the irritating side effect of two state changes in the mutex. In addition, WaitOne and ReleaseMutex can throw exceptions and that further complicates matters. If WaitOne is successful and returns true, and if ReleaseMutex throws an exception, I can't clean up the mess that I have made.
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Jun 3, 2010
There isa xml file about 30 mb size. we are reading text of this file and assigning to a string variable.Then it occupy sapce in memory. But after comes out from method memory still not released. I also set variable to nothing.It still not released.[code]When i close the application.Then all the memory release. Or when i use the GC.GetTotalMemory(True) after st=nothing. Then most of the memory release not completely. I am checking the memory usage from Task manager and process explorer.
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Jan 7, 2011
When running a program in VS debug mode, I use the Debug.Print and watch the Immidiate Window. I'm sure there are more advanced ways to debug, but I haven't learned so far.
But I would like to know how is the best way to track both log of exceptions as well as in-code specific method print-outs (like Debug.Print), during "released" runtime; outside VS.
I would like for two purpose:
Write to log text-file
Write to UI window, like a rich-textbox.
Is this a case I should use Console.Writline? I have never used that, so if you could briefly explain if this is the right tool for what I want to accomplish, or what other ways I should consider.
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Jul 30, 2009
I can define a NEW sub that runs when an object is instantiated. What is the correct sub to call when it is disposed? I would think a method named dispose, but I seem to remember somewhere that there is a better choice than dispose.
Why do I care? I want to be able to track when a given object is released.
With a form, I can use formClosing, but what about a simple class definition?
how I would know what to search for to have found it without bugging any of you? everything I tried resulted in way too many hits that had nothing to do with VB or what I wanted to achieve.
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Apr 11, 2012
Private Function GetImageSize(ByVal FileName As String) As Size
Dim ImageSize As Size
Using BR As New BinaryReader(New FileStream(FileName, FileMode.Open))
Do
[code]....
I want to display photos of people when the mouse passes over their name. I wanted to be able to size the picture box to be proportional to the various photographs and let the Stretch property handle the rest.I used the code above offered by John Wein to a question from 2009 to read the dimension of the picture It worked fine until I pass over the same person twice. Then I get an error that the file is in use by another process.I tried adding:
"BR.Close"
With and without
"BR.Dispose"
But the file is still locked-out on the second pass. I tried setting "PictureBox.Image = Nothing" when the mouse leaves the square, still the file is seen as in use and locked.
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May 19, 2009
Is there something that needs to be done with the following code to release the memory it uses?
Dim objImage As MemoryStream
Dim objwebClient As WebClient
Dim sURL As String = Trim(m_StationInterface.PicLocation)
[Code].....
The code is on a popup form that shouldn't ever get disposed. A new image is loaded onto the form every time it pops up. However, the process size for the application continues to grow each time it makes it through that code block.
I've tried objImage.Close() and .Flush(), objWebClient.Dispose(). The process size still grows by a good 4mb after every call. It's like the old image is kept in memory.
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Feb 19, 2010
I have a VB program that displays a PDF file. When the program is closed it takes 30 seconds or so before AcroRd32 process releases the PDF file. In certain circumstances if the program is restarted with in this period, the PDF file does not display. The specific circumstances is that I have a second program (re)starting the program that displays the PDF file.
a) Make the PDF file be immediately released when my program closes
b) When the PDF file is loaded test that it properly loaded so that it can be reloaded if necessary.
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Sep 1, 2009
in a winform, in vb net,I have a list view with hoverselection set to true. I start a drag and drop operation when the mousedown event is fired, but it's fired only when i release the mouse button on the control or on the dropped control!
is it a normal behavior?
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May 17, 2010
I've created a simple Windows Forms Application and the idea is I want to identify all instances of Excel, save any open workbooks to my desktop and close all the Excel instances down.[code]I'm pretty new to this C# business so hints on the following two possible issues I've identified would be much appreciated:The ForEach loop doesn't seem to be successfully looping through the XlApp.Workbooks collection as I was hoping.
It seems that I can't quit each Excel application which, with my current code structure, is causing an infinite loop. My suspicion is that Marshal.GetActiveObject() is locking it up and preventing it from closing?If nothing obvious jumps out then I might try the alternative method by Andrew Whitechapel mentioned and linked to on this thread.
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Aug 2, 2011
I have a program designed in VB.net for a wafer probing system. The software has 3 main components that come standard and three that are options. When a customer decides not to have the three options they are disabled but still in the program. If at some point they decide to buy the options, one of our technicians would have to go there and be able to access the program with an administrative account to enabled the components.
Does anyone have any suggestions on what the easiest way to accomplish this?
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May 10, 2011
This is my problem.I have a field set up in MS Access to Boolean YES/NO, this field is populated when the user check a checkbox on a windows form. If the user check a checkbox, the value is written as checked in the data field (MS Access).The problem is when I search for the user information, I need the information from the Data base to populate(return) to the windows form. Example: If I enter a users phone number and the user data is present, the form gets populated with the information the user previously entered which was store in the database.Example: If the user selected checkbox1 and submits the form. When I search for the user info, the check box should check(populate) because the user had checked it on submit.Here is what I have done:
[code]...
I am getting the check value correctly in the database using a Boolean.Here is one of the errors I am getting. Unable to cast object of type
'System.Boolean' to type 'System.Windows.Forms.CheckBox.I am having trouble putting the codes in a code tag or block
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Dec 15, 2011
My application is like this : i have to search my data from database with some check box and text box when user select check box specific function go on and then when user enters some range of value in textbox then the result will shown in data grid view after that i can print it by selecting data
my vb.net code is as follow:
Imports System.Data
Imports System.Data.SqlClient
Public Class XtraForm1
[CODE]............
I m also pasting the demo picture.
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Apr 9, 2010
Details: I want to compare these above two table1 and 2 . The unmatched records should be save in a new table .
objectives
1 Should take input the table and fields we want to match each other.
2 Then after searching or reading the record from table and selected fields save the unmatch records in a new table
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Oct 8, 2009
hi there,first of i know nothing at all and my goal is to make a app for xp to check a database and check/patch a iso and then to burn the result to dvd-dl, basically like a app called abgx360 checks the database then like xbox backup creator burns the game, i'd like to make a app to do both, i'm going to college next year in september to learn programing c+ andf a few other things, but thats a longtime away.
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Jan 17, 2010
Is there a way to check specific pixels in a picturebox to check the color? Basically what I have is a black square with some white dots, and I want to find the position's in the picture of the white dots.
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May 9, 2011
I have a Boolean that writes to a data field. The data field(column) is set to YES/NO, if the user check a checkbox, the value is written as check in the data field.The problem is when I search for the user information, I need to get to form to the state it was in when the user submitted it.
Example: If the use select checkbox1 and submits the form. When I search the form, I need to make that particular check box check.
[Code]...
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Oct 23, 2008
I use check boxes and place them on my user interface (See attachment)I have coded the code for "select all" button :
Code:
Private Sub checkedall_Click(ByVal sender As System.Object, ByVal e As_
System.EventArgs) Handles checkedall.Click
Dim chkboxes, outs As New Collection()
[code]....
I could not seems to check all the boxes. Is there something wrong with it? I am not sure how to assign array to check boxes.
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Jul 11, 2011
A couple of questions about check list boxes:
How to check/decheck all the item in the list How do you copy or delete all checked items in the list
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Jun 4, 2011
How to check a check box based on a condition at run time?
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Mar 6, 2010
How can i allow the user to only check one check box on a CheckedListBox1..I was thinking of using a timer but that might be a stupid thing to do.
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Aug 1, 2011
spell check class? How to use it to spell check textboxes in real time?
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Mar 11, 2010
Is there any code that will make possible check if the user typed a word i want in order to show him something ? something like , if the user types time , or tim or timing or the word time and transformated to show him up the time ..
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Jul 11, 2010
i am new to the whole visual basic deal altogether and i'm sure i jumped into the hardest version. anyway i am trying to make a program for my band director so that when he checks-in/out uniforms its faster and easier. i have the checkout done but the check in is a bit of a trick. i need to read the data in from the file and whenever ", " that character is read it need to go to the next text box so it starts with textbox1 which is lastname and goes to textbox6.
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May 2, 2012
[code]......
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Mar 7, 2011
how to check and uncheck all asp.net checkbox on single checkbox check ?I have 5 asp.net checkbox on webform i want when 1 single checkbox checked then all checkbox will be cchecked and if checkbox is unchecked then all checkb ox will be unchecked ..
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Feb 18, 2010
I recently stumbled across people checking for the 'Nothing' value in a interesting way(interesting to me at least).[code]....
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