VS 2010 Does 'Dim Var As New Object' Delete Previous Instances Of The Same 'var'?
Oct 12, 2011
I am just getting started with VB.NET - what I couldn't find in my book is whether a new instance of an object with the same variable-name will delete the previously stored values - or will that somehow remain in memory?This is the scenario:
I open a data file and load the contents in 'Dim var As New dataObject'what happens when I again open another file and the same line is encountered:Dim var As New dataObject'
Hope the question is clear p.s. the dataObject is a simple structure with a bunch of variables in it - nothing fancy.
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Jun 23, 2010
Like i have. Dim MainWindow as new Classic.
But i have another i need to Access.
Is there a Way. Ive Tried and Tried. But i can't find a Way to Load another.
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May 3, 2010
I am making a small and very simple game that is ment to help children learn to recognise letters. I have come to a stop as I have 3 text fields. When something is entered into the first field, the program will set focus to the next text field. The problem is when the child tries to delete a character from a previous field as the focus is already set to the next text field. I want it to delete the character from the previous field when the backspace bar is hit. Any suggestion how this might be done?
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Nov 21, 2006
I'm trying to create 3 instances of the the Workshop selector form for the 3 individuals that I have inthe listbox to appear when I first run the program.
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Nov 6, 2009
Is it possible to look for all current instances of a specified object without specifically IDing each instance as it's created?
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May 12, 2009
can i do some thing like this in .net? and how?
Code:
dim object1 as new clsDatadim object2 as object
object2 = getobject("object1")
"getobject" function is my "needed function"
the purpose is to set object2 to have same memory address with object1 so if i change the properties of object2 then the properties of object1 also changes..
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Nov 19, 2009
this is probably something I should know, but I'm puzzled by this.I'm trying to create some objects and being able to access and modify these globally. I tried to create a Public Module and declare a few objects in this.I am able to access these from another sub, but I get an exception error when after building and runing the process and trying to modify these object. The same thing happens if I declare the object in the Public Class Form1. For example like this:
Public Class Form1
Public appWord = New Microsoft.Office.Interop.Word.Application
Public wordDoc as Microsoft.Office.Interop.Word.Document
[code]....
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Jun 24, 2011
In my form, I have textbox + combobox to enter datas which are saved to ms access. I have search option too. Also i have DataGrid to show the result of the search. What I want now is, 1. To show the search result in the textbox/combox as well (I already am able to make the result show on datagrid)2. When there are multiple result showing on DataGrid, if i click on a particular result on DataGrid, let the textbox/combobox automatically loads the details of the one i clicked.
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May 23, 2011
Is it possible to recall a string or object that was stored in a previous sub? The below code gives you an idea as to what I am trying to do.
Sub StoreUserData()
Dim StorName as Object
End
Sub WriteUserFile()
'Recall StorName here
End Sub
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Sep 5, 2009
having difficulty with understanding object lifetime / instantiation.I have a windows from with a datagridview and a panel. The datagridview has a checkbox column and a list of names which is populated from a database.The panel has a few text boxes (e.g. name, age, favourite sports team) and a 'save changes' button.
The idea is that when the user selects a person in the datagridview by checking the appropriate checkbox then the panel shows the relevant data for that person (name, age, fav sports team) by pulling the data from a database. If the user would like to update the person's details they can do so by typing in the textboxes and then clicking the 'save changes' button. All quite simple so far.
The way I have designed this is to have a 'panel' class and to create an instance when the user checks a checkbox.(NB - the reason I have created a 'panel' class is that I intend to replicate the datagridview and panel on other tabpages within my form and thought it would be useful to have a generic 'panel' class that I could re-use.)
My code looks a bit like this:
If CheckBoxClicked Then
Dim UpdatePanel As New UpdatePanel(MyForm.NameTextBox, MyForm.AgeTextBox, MyForm.FavSportTeamTextBox, MyForm.SaveButton)
UpdatePanel.GetData()
...
When the user clicks the SaveButton the data is updated to the database and I have a display message (simple textbox) which says "Update successful" and displays for 5 seconds before hiding itself.
Here is the problem:Suppose a user checks a checkbox, reviews the data and does not make any changes, and then checks another checkbox and decides to update the data by clicking the 'save changes' button. What happens is that the "Update successful" message is displayed twice.
I think this is because every time the user checks a checkbox an instance of UpdatePanel is created. If a I select five different people using the checkboxes and then hit 'save changes' I get five "Update successful" messages.
I am not sure how to overcome this. It feels like each time a checkbox is clicked I need to check if an instance of UpdatePanel exists and then destroy it. I tried using UpdatePanel = Nothing and also investigated IDisposable and GC.Collect() but with no luck.
[code]....
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Jun 21, 2012
I have a need for a button to take the user back to their previous page.Because of how this page is accessed, the only way to do this is with javascript using history.back()
This part works perfectly apart from the fact when a user goes to click a button on the page they have gone to back to, I get the error that Request.QueryString is not supported in this context.I'm guessing the Request object is lost when javascript is directing the user to the previous page.I cannot use Request.UrlReffer either because the the nature of the back button. (it causes a loop at times).
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Oct 27, 2009
I am having a problem with a and OOP class i made that contains a sub that creates random integers.
Problem is if i define two instances of this class and configure them(name in this case) then they both display different names but the random integers are ALWAY the same. in this case having the integers the same kinda kills the idea of the program.
Is it possible that the random part only every works for one class, but if .NET is fully OOP then this should not be possible... right?
Some of my Code (broken down to something smaller) i will display for obvious reasons.
Code:
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Jul 15, 2010
I have a problem with a generic list, which consists of intances of a class i created. I am just amazed, each time I add a new object to the list, it overwrites the previous entries. Here is a code sample, i just can't beleive it. I am using visual studio 2010:
Dim translations As List(Of TranslatedValue) = New List(Of TranslatedValue)
If Session("ctlTexts") Is Nothing Then
Dim reader As IDataReader = DataAccessFunctions.db.GetDataReader("SELECT [ControlID], [ControlTextEN], [ControlTextDE], [ControlTextBG] FROM [dbo].[tbLanguage]", GetConnectionString)
[code]....
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Aug 19, 2011
If I create a DLL using VB 2010 express can it be used by previous versions of of .Net (3.5, 2.0)? Will the DLL use .Net 4.0 components, which is what I want. I don't see a way to force that to be the case.
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Jul 16, 2011
In Datagridview, Set as DatagridView1.ReadOnly=True,
Dgv1.Rows.Add()
When i tried to add a Row, it is copying previous Row data to new row,and also blank the previous row, why?Like Insert Row, Why...?
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Sep 22, 2010
I'm working on a program that uses a COM Object exposed by a .dll. The .dll has a known bug, though, where it acts very erratically when more than one instance of the object is created under one .dll, resulting in crashes or corrupted data a large part of the time. I'm curious if there is some way I can load another instance of the .dll itself, then create another instance of the object without having to need a new process for every instance.
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Mar 16, 2011
I'm trying to delete a number of records in a table from the last and forward. My idea is to use sql like this: delete top " & variable & " * from table where ID = something It gives me a general sytax error. Is it at all possible? Fuga. Edit: I also have the order by statement there. I just forgot to put it in the question.
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Sep 17, 2010
I have a TabControl object on my form with many tabs created in code (TabPages) and my problem is that the same objects that are in the initial TabPage needs to be in the other TabPages created in code, I have this done in code when the user clicks the 'New Tab' menu option, however the same code is used for any new tabs created. The problem created here is that I have an event against one of the objects that appear in the other TabPages, but because the same code is used to create any new tab pages, the event will only work on the newest tab page, if that makes sense? By the way these objects that appear on the other TabPages are properties at the top so events can be handled against them in the respective subroutine.
[Code]...
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Jan 24, 2012
I'm a little out of my comfort zone here having programmed in VB6 quite a few years ago things have changed a lot since then.My issue is I have a class that I've built which works with no issues but I would like to be able to keep a 'handle' of some description on this class so I can also make adjustments to it's parameters when the user changes something. My problem is that I need to do this for an unknown quantity of these class instances.
In the VB.Net language how would I create an instance of this class that could be accessed by any Sub within the application and each instance created can be individually accessed by specifying some sort of identifier?
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Jul 31, 2011
I'm creating a twitter account manager using the Twitter API. I have multiple accounts, over 10 of them. I want to automate all 10 of these accounts to do certain things, now the way I started to code the program was so that it would accommodate only one account, and all the codes worked perfectly and were managed by individual timers for individual processes that I wanted done. i could tweet between certain intervals, follow people who tweet certain things without me being on top of it.
Now the problem is that I've been trying to create new instances of subs that I've already created so that I dont have to create 10 new subs with the exact same procedures. I'm pretty sure it's impossible to create copies of subs dynamically or within a loop but it didn't stop me from trying. So question is how can I edit a program that was designed to accommodate and automate only one account, to potentially accommodate over a 100? I don't need codes or anything I need ideas so I can try them, but right now I'm completely blank.
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Sep 24, 2011
How would I go about counting the number of times a given query occurs inside of a text file using LINQ?I need to search through the attached file and see how many justices were appointed by each president, and then create a new text file displaying the following:
presName, justiceCounter 'president name ordered by first name, number of justices appointed
I pretty much get how to do everything except for keeping an accurate counter within the LINQ query. However, I do feel confused about the order in which I should write this code, as in where I should keep my counter for how many justices a given president has appointed.
My output is displaying like this:
Abraham Lincoln,111
Abraham Lincoln,111
Abraham Lincoln,111
[code]....
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Jun 6, 2012
I'm trying to code to run 2 instances of the same client at the same time.Using a simple form with a button with system.dyecnostic.process.start(program path) to run the instance to start with.Now the problem starts with trying to run a second it just loads and closes and sends me to the first. how to negate this so I can get 2+ of the clients up?
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Oct 12, 2011
I have a problem that can be best solved with LINQ. I have a class that has 2 properties of which 1 is a single. I have a collection of that class and I need to select the instance with the highest single value.[code]I'm having a hard time explaining this even this is a simple task. Please ask if you don't understand.In addition to my original question, How would I create a collection containing the 5 highest Instances.
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Nov 13, 2010
txtSubject1Info.SelectionStart = txtSubject1Info.Find("Hey!")
I am finding specific words in the RichTextBox (in this case, "Hey!") and selecting them by getting their initial position through the "Find" command. Unfortunately, this does not work when I have multiple instances of "Hey!" in the RichTextBox. Here's an example:
Text in RichTextBox:
Hey! This is cool!
The Find command would return a value of 0 in this case. However, let's take a look at another scenario:
Text in RichTextBox:
In this case, the Find command would return a value of 0 again, but I want it to get the initial position of the second "Hey!" statement. I'm wondering how I can do this.
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Mar 1, 2012
I am using a message queue successfully as I am testing while I am writing a new program. (This is my first time using a message queue.) I have to have multiple instances of my program running, so I was wondering if this would be a problem with the queue? I have tested it and it looks fine, but I didn't know if it is by coincidence, or if the queues were separate.
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Jan 30, 2012
I made a bowling program, it adds 5 scores from 1 player and then calculates the average. Problem is with my reset button, when i click reset it doesn't change "Enter Bowling score for game #1" to 1, how do I change it to 1?
<code>
Public Class frmLab2
'This is a program calculates the average scores of 5 bowling games using array.
Dim scoreCount As Integer = 1
Dim intcount, total As Double
Dim i As Integer = 0
Dim arrscores(4) As Double
[Code] .....
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Jan 25, 2012
I'm trying to figure out a way to sort the entries of a listbox... but in a different way instead of the obvious one (sorted property). First of all, I need to explain how the items are populated at first:
[Code]...
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Apr 23, 2012
I have a program which is made with 12 labels, the first set of six are randomly generated and the second set are values obtained from the first set and the user has to choose in ascending order the numbers on the first set.The values chosen will be trasferred to the second set and then with a "check" button that set of labels have to be rearranged and compared to the user input.If the user for example manage to choose the right order, he will obtained a 6 of 6 and he will recieve a message.My problem is on the rearrage and compare part.
The code I made is very simple but is not working, basically it only check if the next value is smaller that the previous and changed its back color according to the case.
Here the code:
'check button
Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
Dim Score As Integer
Score = 1
[code]....
I would like to have a correct rearrange of the numbers and introduce a message according to the accuracy of the user.
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Nov 26, 2011
I'm trying to delete a record from an access database using the command object in vb.net 2010 express but can't seem to get anywhere.If I run the code below, I get no errors but nothing happens. The connection opens fine but the db does not update.the table has only two columns.The variable strCrit is so that I can build the sql string with exclamation marks, When I debug.print the sqlupdate string it seems to read fine.the routine is called from a form with a button.
Dim sqlupdate As String
Dim strcrit As String
strcrit = """"[code].......
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Jun 13, 2012
I have an XML file that looks like
[Code]....
I am trying to delete the song node from the xml file but i can't figure out the cause of the error I'm getting. I'm still learning visual basics. Error: Object reference not set to an instance of an object. This is my code
[Code]....
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