When And Why Need To Use GC.Collect()
Jan 24, 2012
My application waits for the user to click twice to draw a rectangle on an image, and use the rectangle to create a clone and save it. Then it restarts with the next rectangle. When I work on a large image (10800x7236) after a few cycles I get an out of memory error. but I still don't understand what's going on, and I would appreciate if some expert out there clarified why it didn't work before and it works now. This is the snippet executed after the user clicks twice, and fails after 5-6 cycles:
[Code]....
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Mar 11, 2012
I currently have code that creates and inserts ~175,000 names into a table.
What is the quickest way to collect a random first and last name? So far I have tried, Reading from two text files where every name is one line it takes ~2:30 minutes Reading from a table with [first][last] columns takes ~4 minutes
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Sep 12, 2011
I have a multi-user app which consists of a Windows form (VS2008), and a SQL Express 2008 database. I'm already detecting if the dataset has changed before the user closes the form so I can prompt them to save their changes. What I'd like to do is to capture the changes they've made, and write them to a database table so that users can track all changes made to each record on the DB.What is the best way to grab hold of the data changes before they're written back to the DB and also grab the original records?
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Nov 18, 2009
I have a SQL server table that has a list of Usernames and a list of points ranging from 1 to 10,000.I want to display the number of points in my VB.NET program from the username given. For example, if I type in "john" in the first box the program will give me a message box saying whatever amount of points "john" has. I'm not really sure about
This is the Table Structure:
Usernames Points
-----------------------------
[code].....
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Jul 27, 2011
I have a class orderItem it is a parent of Product and service class Im adding product or services in a listcollection. How can I cast service or product for retrieving orderitem?
Public MustInherit Class OrderItem
Private m_enuItemType As TypeOfItem = TypeOfItem.None
Private m_strUserID As String = ""
[Code]....
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Jun 12, 2010
I have 4 textboxs in my new form. and each of them, i want the data from the db show in the txtbox.[code]...
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Feb 5, 2009
I collect two sets of data from two different databases, This data is now in two collections. I then join/append the one collection to the other and then put it in to a list view.I really would like to order this list view by the first column without the click event.To make this even harder the First column contains Data that is DateTime and i have found that it orders the items by the day number and not the months or years or time.I have found one way but it then cause's me further agony when doing some checks upon the data within the listview later in my code. This answer is to rearrange the format to "yyyy-MM-dd HH:mm:SS" then using the listview.sorting = sortorder.
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Mar 11, 2010
i want to create an application that collect data from the rs-232.Someone have a code example with multi rs-232 in thread .I have one pc that have mapping virtual com.
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Dec 31, 2010
What I need to do is have my application check to see if the last hour that was inserted into the database table is equal to the current hour minus 1 hour when it runs. If it is not equal to the current hour -1 then it needs to go back and download the missing data automatically.
The hours go from 1 to 24 with midnight being the 24th hour as you'll see in my code. My problem is I don't know how to code what I'm trying to do.
Here is the current code:
Private Sub HourDownload()
DeleteFileHour()
If OneHour("C:abcd.pfx", "******") = True Then
[Code]....
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Feb 1, 2011
I'm using the .NET SerialPort class to communicate with gauges. Every time a button on a gauge is pressed a reading value is sent over port. The problem I have is that if the gauge button is pressed while the program is off then when the program starts it fires the data received event for that existing data. I don't want this behavior -- I only want to collect readings done after the port is opened.
port = New SerialPort("COM1", 9600, Parity.None, 8, StopBits.One)
port.Open()
port.DtrEnable = True
System.Threading.Thread.Sleep(100)
port.ReadExisting()
AddHandler port.DataReceived, AddressOf PortDataReceived
If I don't have the Thread.Sleep then the DataReceived event is fired for the previous gauge data. I'm guessing this is because the ReadExisting doesn't block and so when its called immediately after an open it just reads nothing. So if you call 'port.BytesToRead()' immediately after open its zero. If you call it 100ms after open its non-zero. I guess this makes sense -- it takes time after open to read the existing data. Another option is to call read and set the read timeout but that seems no different than Thread.Sleep except you have to catch an exception...
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Dec 10, 2009
I have a windows app (2.0 framework) that's about 860k in size, just a small db app with a couple of data entry screens and a few reports (Cystal) I noticed that when the app starts the mem usage according to task manager is ~11,000k viewing just one report jumps the mem usage to 56,000k. i thought i could reclaim some of that memory by adding some GC.COLLECT() callls, but no luck. Mem usage stays the same in task manager.
So I made an even smaller test app with two forms....Form1 has two buttons , button1 Opens Form2, and button 2 calls GC.COLLECT()
From 2 contains a datagridview and 1 button. The form load for form2 executes the fill for the dataset that populates the datagridview and the button on Form 2 closes the form.
Here's the code for each form....
CODE:
No matter what I've tried so far I cannot seem to reclaim mem that gets used.
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Aug 11, 2010
I am running into an issue with phrasing the following XML. I need to load the content into a object that is outline in the second code block. I am looking for all items to be Property flags within the Object.
<MigrationType>
<MigrationOption id="1">
<NAME>Project Configuration</NAME>
<DISPLAY>TRUE</DISPLAY>
<PAGE id="1">RequiredItems</PAGE>
[Code]...
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Jan 29, 2011
I have an application (i've been working on for a long time) that has many tabs and controls and quite a few components And a good deal of design code. And a list box that has around 100k items (i had to put a loader to pass the 3-4 seconds while its loading to prevent it from not-responding)I had a few Gc.collect calls in specific places (mostly after many items are added or removed). When my application loads, i call GC.collect only once at the end of the load. The program consumes around 35K memory by the time its loaded. However, i decided to mess around abit (don't worry i made backups)First i started putting gc.collect in some random places, and to my surprise the memory upon loading was observably decreasing. Then I went ahead and put a macro that puts GC.Collect before every End Sub, Exit Function, Exit Sub, and Return value, there is. Basically every block in my application had atleat one GC.Collect.
I fixed some 6 or 7 silly replace errors and compiled. When the program launched, the memory used at the end of launch was 21K!
At first glance that seemed great, but then i realized switching between tabs was VERY glitchy. and adding new lists took around 10x more time than usual (the loader stayed on for around 20 seconds!) And even though the memory looked good, the program was useless like this.Then i decided to mess around differently. I removed GC.Collect from the entire solution. It was no longer called even once.At first glance, when i launched the app it consumed just under 60K memory. That seemed terrible. However i realized something: even though my program in that state showed on taskmanager that it was consuming alot more memory than usual, it seemed like it was lighter than ever! Switching tabs was faster than before, especially every time i go to the tab that has the listbox control with 100k items. Loading items took around 3-4 seconds, but there was no stutter when the list finished loading whereas before it had an evident 0.3s stutter after the items were added.
This was all surprising to me because i thought GC.Collect was first of all, something that it doesnt matter where or how many times you call it. I thought it was just something that should be called at the end of work and i didnt think it would matter if it was called during work.Second of all, i thought GC.Collect only affected resources that are inaccessible, or resources my program is done with. How come the application feels faster when i don't call it?Third of all, i thought the VB CLR does most of the memory cleaning for me, and that GC.Collect was somewhat of a redundant command. It didn't seem so redundant to me at all considering the difference between using it heavily and not using it at all was around 38K in memory usage!
So i guess my questions are:
1) Do I need to call GC.Collect? WhereWhen do i call it?2) Why does calling it affect performance? And where does one draw the line between that memory stat on taskmanager and the program's performance?3) I also decided to run a small test. Why does a blank vb form application require 10K memory? How accurate is that stat shown on the task manager?
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Jul 31, 2011
In my program; I need to collect a sequence of events in a variable of some sort. Each time the Sub is initiated, it should add one random event to the sequence (so that it gets longer each time) and then run through the sequence.This is rather difficult to express.What I'm trying to do, is create a Simon Says game with the four buttons.After the sequence goes through blinking the buttons, the program must then be able to capture the sequence of button presses by the user and match that to the sequence that the program ran.So, I need to be able to keep track of two sequences in a variable. Arrays?
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Apr 20, 2012
I have a table on my SQL DB call ReportList which is a list of report. I need to go through that list and interrogate the reportserver, eport by report, to populate a table called ReportParameters. The ReportParameters table has a column for ReportOwnerID which needs to contains the ReportID value of the corresponding (owner) report as listed in the ReportList table.
It needs to work so:- I have a listbox of the reports as per REportList and a GridView that list all the parameters (uniquely - most of the parameters are common to many reports) the idea being that the parameters get set once and the report can be kicked off by selecting them in the ReportList CheckListBox and clicking on Execute. I would like it that as I click on a particular report in the ListView, the relevant parameters in the Gridview get a green background and those that do not apply are red. The leftmost column in the gridview contains tha Parameter NAME (not editable) and the next column must be editable to populate the value.
Done so far: I have tried on clicking the Execute button, to build a parameters string in a testbox and call that with the Javascript OpenReportWin() function when I open the report in a new window. This works fine, but my biggest issue it interrogating the reportserver reports to get back a list of parameters and dooping them into a table. I have tried to use a hidden DataGrid bound to a ds onto the reportParamaters table.
I have tried to populate it using a datalist but I cannot get the hang of these thionsg and its looking messy. Their must be a simple clean way of getting the .GetParameters resultset back from the report server and populating the table without having to create a reportviewer object and cycling through the list of reports - it then has to render each report before you can get that list out.
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May 10, 2012
I get a problem with my program. My program should do :
-Explore folders from a main folder (LOGS)
-See if there are csv files
-Copy the data from CSV (all informations are on the first column)
-Paste it in one xls file (with a sheet for every csv)[code]...
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Jan 11, 2009
I am just trying to get the information i collect from the pc's hostname and pass it into a db. All the db passwords, location etc are correct but i am getting nothing.
Imports System
Imports Microsoft.Win32
Imports System.Data
Imports System.Data.SqlClient
Public Class Form1
Private Sub DB()
[Code] ......
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Dec 25, 2011
collect information from core temp ( how to gain information about the CPU directly from the motherboard or windows E.G temperature CPU name ) and use it as a variable within VB.
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Feb 15, 2012
collect username and password from database for login?
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Jan 4, 2010
I have an access database with 3 tables, want to collect data from 2 and insert them into a new row in the third (although this seems redundant there are reasons for wanting it that way). I created a form and call the data from the two tables fine, once the form is filled I try to add a new row to the third but it will not add the row even though it is telling me that is has. When I open my access table the record is not there. I am new at this and just can't figure out why it won't work, I have tried several approaches the latest is
Code:
Private Sub Form3_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Me.Activate()
Dim IDNUM As String = InputBox("Enter Student ID Number")
'storing the text entered in a string
[Code] .....
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Jun 10, 2011
I have a routine that is supposed to grab all email addresses within a certain group. The email address list can be well over 1000 emails. When emailing it out though I can only send around 150 emails at a time. So what I i've done is executed a query and threw all the emails into a collection.
How do I now reiterate through the collection grab 100 addresses each time and call the routine to email that group?
Dim emailToGroup As String = ddlEmailTo.SelectedValue
Dim connStr As String = ConfigurationManager.ConnectionStrings("SNA_TRT").ConnectionString
[Code]....
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Jun 27, 2010
How can I collect details regarding the hardware and software, of a PC? As for registration process of the product (my app), I wish to collect the details of that PC and get it saved into my server.When the client request for a new serial key, because of formatting the PC and other reasons, I would compare the PC details and will issue a new serial key based on the result. (small changes in the PC will not be considered)?
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Dec 22, 2009
I have a function that returns a date. I want to use a modal window to get the datte value from the user and pass it into the function.
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Apr 17, 2010
I have list of urls that I use a foreach loop on. I want to visit each url with the webbrowser and collect html, but the webbrowser only collects the html of the last url. I think the loop is too fast?
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
Dim Collecthtml As String = ""
Dim websitelist As List(Of String) = GetURLs()
[code]....
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Dec 4, 2011
I just started learning .NET and im creating my first little program. the program its to collect all websites in server and for that im using sitedossier to collect, but i have problem with regex. When its my mistake here i still beginner in that language. [Code]
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Nov 5, 2011
We use a database to create Data Collection forms with dynamic items
I used this code to generate labels and textboxes from a table in database (when the user hits the button "load CRF")
Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click[code]...
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May 4, 2011
I have just written an app in VB 2010 with .NET 4.0 that contacts our field loggers to collect data via modem or IP. Originally it was written without threading, but now the requirements have changed and I need to collect data simultaneously from 4-6 sites at a time. I have never used threading, TPL, etc. Can anybody tell me where to begin so that I can concurrently run multiple collections?
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May 1, 2012
I have a problem with an application, in this case I have a windows services. its function is generate reports depending of demand of our users.In some cases the memory usage of my windows services is to 2 gb of RAM. I disposed all objects that my application use . but the memory usage doesn't low.I tried to reduce the memory usage forcing to garbage collector to Collect with the method "GC.Collect"but it's not recommend because uses many time of CPU.Surfing on the internet I found a method named "SetProcessWorkingSetSize" that free memory usage correctly. http:[url]....but some cases my windows services named sapdkadm_procesoestandarejecucion.exe has some error message in event viewer is the next:
Faulting application sapdkadm_procesoestandarejecucion.exe, version 1.0.0.0, stamp 4f908fef, faulting module kernel32.dll, version 5.2.3790.4480, stamp 49c51cdd, debug? 0, fault address 0x0000000000027ded.
The real problem is that when this happens my windows services restart
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Mar 27, 2012
We are creating a VB program for school to collect data on student attendance and populate it to a table. I have all of the 'GET' statements but am having trouble creating the 'Insert' procedure. This is what I have so far. The form being used to fill the table has 4 items being recorded. 'Present' radio button marked as present, tardy or absent; StudentId, PeriodId and date. Not sure if we are on the right track. The target table is tmAttendance. There are approximately 25 rows of data on the input form.
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Oct 1, 2009
How can I Collect all the Checked Child Nodes Name From a TreeView Control Using VB.NET Windows Applications.
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