VS 2010 - List(Of ).Clear() - Load Several Lists Of Codes From A Database Depending On The Import Selected By The User
Dec 29, 2011
When .Clear() is invoked, is the memory freed up that was allocated when all of the items were added? I need to load several lists of codes from a database depending on the import selected by the user. Each list of codes will be a List(Of String). My idea is that I will load only small strings into a List(Of String) along with a List(Of <class>) for the data I will be validating and manipulating. When I am done, I want all of the data from the Lists to be purged from memory. Will .Clear() take care of that or does the memory still remain allocated and have to be dumped by the OS once memory gets full? (And, incidentally, what causes the OS to decide which memory blocks to dump? FIFO concept?)
There are so many lists, I'm not sure if I just want them sitting in memory or not. Granted, the lists will just consist of a single string value for each code pulled from the database. So there won't be a ton of data, so maybe I could just load all the validation lists at the beginning of runtime and only worry about purging the data List since it will contain between 35-50 "fields" per record and there will be a couple thousand records each import that is run. I don't want my program to actually cause a hit in performance in the long run. I ultimately don't see a problem because I won't be running millions or even hundreds of thousands of records at once, but I just want to be sure.
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Jan 18, 2012
I seem to be having issues with the selected index on a list box.
The list box is having various items inserted depending on the user selection. An example would be:
LiIndex = ListBox1.Items.Count
ListBox1.Items.Insert(LiIndex, "Item1")
LiIndex = ListBox1.Items.Count
ListBox1.Items.Insert(LiIndex, "AND")
[CODE]......................
This all work and displays without a problem. The issue I have is if I select the second of the two AND's. If I click the second "AND" in the list and then a button to fire a method, the selected index is always the index of the first "AND". Dim listIndex as integer = ListBox1.SelectedIndex
I can't work out why, the listbox itself will always show the second one as selected, but the action will happen against the first one.
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Jun 21, 2010
I have connected a form to my database, which displays info when the form loads, butttt it displays them from load, which is not what I need, can someone tell me how to clear the form upon load so that none of the textbox fierlds have data within them? Untill I request them to.
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Sep 25, 2011
When I run the program it will populate the listview but when i delete the selected item it will clear all of my records in my listview. . . .can anyone elp me with this??This is my code. . . .
[Code]...
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Jun 22, 2010
I have a vb .NET 2005 form that needs to load data based on a selected month by the user. Because there is a large amount of data in the table (60k+ records per month) it is taking the query a long time to pull the dataset back and populate the form. how I can decrease the overhead associated with querying a large dataset to populate a base form?
Note, I have created an identity key on the main table but haven't yet indexed any other fields (Though I could use some suggestions on how I should index).
See the following example of the Stored Proc that is run before my .net form is launched:
Dim cmd2 As New SqlCommand
Dim ConnectionString As String
Dim TheDatabase As System.Data.SqlClient.SqlConnection
[CODE]...
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Jun 21, 2010
My below codes in a button click event populate data in the grid upon the user click the button.
1. How do I know that my commandtext did not find any matching data to popup the message to the user - No Records found.
2. How do I clear the data in the grid before executing the below codes.
--conection to SQL Server is opened
myadaptor.SelectCommand = New SqlCommand
myadaptor.SelectCommand.Connection = myconection
[code]....
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Feb 2, 2011
How do you clear the Recently Opened Program Lists in the start menu?
I've been making a computer cleaner, and I've Googeling and I guess binging so much to find an answer but i couldn't, does any1 know how?
The most I could find was: [URL]
BTW I know how to clear it, but I need to know with VB code.
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May 28, 2010
I have a contact manager program and I would like to offer the feature to import csv files. The problem is that different data sources order the fields in different ways.I thought of programming an interface for the user to tell it the field order and how to handle exceptions.Here is an example line in one of many possible field orders:
"ID#","Name","Rank","Address1","Address2","City","State","Country","Zip","Phone#","Email","Join Date","Sponsor ID","Sponsor Name"[code]....
Notice that in one data field "Name" there is a comma to separate last name and first name and in another there is not.My plan is to have a line for each field (ie ID, Name, City etc.) and a statement "import to" and list box with options like: Don't Import, Business>Join Date, First Name, Zip
and the program recognizes those as properties of an object...I'd also like the user to be able to record preset field orders so they can re-use them for csv files from the same download source.Then I also need it to check if a record all ready exists(is there a record for Anson Call all ready?) and allow the user to tell it what to do if there is a record(ie mailing address may have changes, so if that field is filled overwrite it, or this mailing address is invalid,leave the current data untouched for this person, overwrite the rest).
While I'm capable of coding this...i'm not very excited about it and I'm wondering if there's a tool or set of tools out there to all ready perform most of this functionality...
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Nov 17, 2010
I have a txt file that is like below.
user1
user2
user3
[code].....
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May 29, 2009
I have created an access database which i want to search with vb.net, I tried a few thing but it didnt work as desired.
Firstly the program is suppose to display items in the database base on the criteria selected by the user. what i've succefssfully done so far is I've added a datagrid 2 combobox, 1 (searchcbo) with the columns in the database and the other (searchcbo1) will autoload the items under the column selected in and a button (searchbtn) but i have no clue of the code to put in the button. i also tried the fill method but that didnt work as i wanted to. ultimately i want a combobox with the list of columns and a textbox to enter criteria and of course a search button.
The searchbtn should act as the "WHERE" sql command, e.g. SELECT EmployeeNumber, Firstname, LastName, Phone, Location....etc FROM CallLog WHERE searchcbo.text = searchcbo1.text And display the results in the datagrid.
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
'TODO: This line of code loads data into the 'CallLogDataSet.CallLog' table. You can move, or remove it, as needed.
Me.CallLogTableAdapter.Fill(Me.CallLogDataSet.CallLog)
[CODE]....................
Attached image(s)
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Aug 3, 2011
So I have a program that is supposed to support a small business. I have the work completed and the professor said it was correct but I wanted to go do a little extra.Basically, on the Order screen, you begin to type the name of a customer/supplier/employee into a text box and a list of names that fit the criteria pops up in a list box (lbMatchingAccounts). When you select it, you can hit enter new order and be transported to the Order Details screen to enter the new order.
What I wanted to do was to create a new list box (lbOrderId). What I want is to be able to select a person from lbMatchingAccounts and have all their Orders populate in lbOrderId.
[Code]...
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May 1, 2012
I am creating a program that allows a user to view a list of foods in a combo box, add that food unto a list box, and adds all of the calories of that food together. When the user highlights their select food, the program automatically shows the amount of calories for that particular food in a text box. The program is getting the food and calorie information from an access database. I managed to get all of the food calories to add up properly, however, I ran into a problem. Sometimes, well, most of the time, when I select certain foods from the combo box, the program automatically reselects another random food, usually a food that begins with either an A, B, or C. Also, the other random food that the program chooses usually has the same amount of calories as the food I originally wanted to choose. I have over 6,000 items in the database. I don't understand why this is happening. This is what my code looks like for the button that adds each food to the list box:
Private Sub Button4_Click(sender As System.Object, e As System.EventArgs) Handles Button4.Click
Foods_Selected.Items.Add(ComboBox1.Text)
Static i As Single
[CODE]...
And this is what my code looks like for the button that adds all of the foods together:
Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
Dim x As Single
Dim TotalCalories As Single
[CODE]...
I have no idea what to try. It's like the program just skips over random foods, even though all of the information for them is in the database.
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Mar 7, 2012
I've got a piece of VB script that runs from a logon script. It contains the line: objShell.run("regedit /s/c \SERVERNETLOGONScriptTest.reg", 0) Which imports a file into the registry just as I want. The /s switch means that I don't get the two warnings from the regedit program which is exactly what I'm looking for but everytime it runs the UAC asks for permission to make changes to the computer which of course I don't want to happen.
[Code]...
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Jun 19, 2012
What is the appropriate declaration such as "ValueChanged" or "Click" for a NumericUpDown that will execute the code when I press enter. I already know that setting the "AcceptButton" property of the main form to a default button will not work, especially if I want a different button to be selected depending on which control I give focus. How do I accomplish this?
PS: Is the syntax any different from Visual Basic 2010 Express than it is on Visual Studio 2012 RC (running in Visual Basic Mode)?
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Jul 4, 2012
I have my rpg, still, first time working on it n ages, and I want each user to be able to set their own personalized picture background for the game...
each character in the game has its own dedicated folder for each file that the character has relating to it...
what I want to know how to do, is to have my game copy the loaded/chosen background image to their respective characters data folder, and have the game reload/reset the games default background image, to the one piced by he player...I am having a hard time figuring out how to do this however...I've tried a lot of different things...and nothing is working yet...
here is my example code right now:
[Code].....
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Apr 15, 2009
I've written a program to work out the flight distance between a set of seven cities around the world using a 2D array but was wondering how I would if possible go about having the values for each city selected via two drop down lists (say start city and destination city).
Public Class frmDistance
Private Sub Flightdist_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim rowcolumn(7, 7) As Integer
Dim sr As IO.StreamReader = IO.File.OpenText("Distance1.Txt")
[code]....
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Nov 6, 2009
I'm trying to play around with combo boxes and trying to figure out how to navigate to a certain url in webbrowser1 depending on the text selected in combobox1.
VB
Imports System.Windows.Forms
Imports System.Net
Imports System.IO
[Code].....
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Jun 22, 2010
I have a web page where I am trying to populate the PSI # into the txtPSI depending on which customer is selected in ddlCustomers. I have written it a way it has worked on a past project and it compiles with no errors, however it doesn't work when it runs.
Protected Sub ddlCustomers_SelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs) Handles ddlCustomers.SelectedIndexChanged
'Populate PSI # in txtPSI based on Customer selected
[CODE]........
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Feb 2, 2011
So here it is : how can iI get info about the file that user selected in windows ? For example: the user browse to C:windows (it isn't important where maybe desktop) through explorer and select a file ( he/she just select it, not open ). the moment that the file is being selected, how can I get info about that file? I think the file path is enough. I can get the rest detail with path.
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Apr 8, 2010
Is there any examples with a treeview like this [URL] /scree...tinel-smod.png is it a case of having to draw each form how you would like to then hide/show the controls depending on what is selected in tree view????
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Jan 17, 2010
I need a compile an exe file which will read vb codes from txt file and run according this.
For example, I will keep different different vb scripts in different filesuch as [code]...
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Mar 29, 2010
I want to choose a value dynamically from comboBox depending of the values selected previously in two comboBoxes.the code that loads the comboBoxes:
Private Sub LightClassComboBox_DropDown(ByVal sender As Object, ByVal e As System.EventArgs) Handles AreaClasificationComboBox.DropDown
TrafficDensityComboBox.DropDown,.....
[code]....
The problem is that in the last Sub in the If sentence gives an error of: Null Reference Exception, because the compiler thinks that in that event the data are not loaded, although the data are loaded when loadcomboBoxes sub is executed.
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Oct 6, 2011
I am writing a program for a class and it needs to read/write to an Access 2007 database. Right now I am referring to it's absolute path when I use it in connection strings, something like:
Dim conn As New OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:UsersMeDocumentsVisual StudioProjectsProject1Database.accdb")
This is going to be a problem when I turn it in obviously, because the professor isn't going to have the same path. So I want to somehow include it into my project and then refer to it with a relative path or something so that it will work on his machine. When I imported it through the Data Sources it had an option at the end to copy the database into the project which I agreed to. It put the Database where all of the source files are on my computer, so I tried using Application.StartupPath(
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Apr 10, 2012
I am trying to populate a combobox with a list of filenames from a selected directory. I am getting the directory OK but the combobox instead of having a list of 8 files max shown when I select the combobox has a full list of all the files selected from that directory.
Private Sub BrowseButton_Click(sender As System.Object, e As System.EventArgs) Handles BrowseButton.Click
If FolderBrowserDialog1.ShowDialog() = DialogResult.OK Then
TextBox1.Text = FolderBrowserDialog1.SelectedPath
End If
[Code].....
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Aug 9, 2011
building simple program that i could print index pictures to 11x17 size paper. and came across with listbox multi items selected and wanted to add them to different picture boxes?
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Aug 15, 2011
what is the best way to load dropdown lists from reference/lookup tables for a desktop application? the application is layed out into 3 tiers. I've built up my entities.the front end has a form with 6 tabs. and one big save (another discussion :)Should I load them all when the form is initially loaded? Are there any caching mechanisms I could use?
it is vb.net app on a network drive that is accessed by several users.it's also worth noting that some reference tables may be updated. Via another form.
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Nov 11, 2011
I have a ListBox and a button. I want the button to be enabled only if the user has selected an item from the ListBox... How do I do this?
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Apr 9, 2009
I need to load a list of tables and linked tables in an MS Access Database into a combo box. I have this.
vb.net Imports System.Data.OleDb
[Code]...
1. How do I load the access tables and the link tables into my combo without the system tables showing up?
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Oct 6, 2009
I have this combobox and I wanted to clear the combobox when click on the clear button. As what I know is that as for the textbox, it is like textbox1.text="" to clear the textbox.
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May 17, 2012
I have a project which has a couple of tabs on form, an usercontrol is on the 2nd tab, when the form loads, i want the load event method of the usercontrol to fire, and the message box should pop up.Please see the attach file, the message box only pop up after the form is loaded and the 2nd tab is clicked, not when just the parent form is loaded.
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