Getting ListView Data To Persist After Shutdown?
Jan 13, 2011
I need some general advice about using ListView. The program was originally written in VB2002, but now it's running in VB2008.The results of my program would typically be a ListView of 30 lines by 8 columns. I need to be able to save this data so that it persists after I close the program. There will never be a need to manipulate the data, so I'm looking for something simple. (There will be a need to print it.) I'm presuming that I need to link to a database to save the data. Correct? If so, can I use the one in Microsoft Works (which I already have), or do I need to get Microsoft Access, or is there some other better (simpler?) alternative?
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May 27, 2011
Let's say an application needs to persist mostly immutable data. Let's say the application's data files can grow fairly large. How would you implement a simple transaction processing so that changes are either successfully committed or rolled back?
The only requirement is to use built-in .Net libraries. (no databases, no third party libraries)
Here's my current solution. The data file will have three main sections: (1) header, (2) data, (3) index. For now, the header section simply contains an offset to the start of the index section. The data section will store mostly immutable data. The index section will contain serialized objects with enough information to access the data section.
When the application starts, it only needs to deserialize objects from index section. Anything from the data section can be fetched as needed. As the application gets ready to write changes, it makes a temporary copy of the original header and index sections. These would be small relative to the data section. New data would then be appended to the original data section. Once all data has been written, in memory objects would be serialized to the end of the file to become the new index section.
If all this goes without a hitch, the temporary file can be deleted. If something goes wrong, the temporary file can be used to restore the data file to its original state.
Will this work or is there a more elegant approach?
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Nov 5, 2009
I've got a small reminder application I wrote in VB Express 2008. The main app autostarts with Windows and sits in the system tray all the time. Now, I need to save the time (sorta timestamp) it closes/terminates to a file. It works fine when the app is terminated by myself but doesn't when when I shutdown/reboot Windows. The code that saves the timestamp to a file resides in FormClosing event. But for some reason it doesn't fire or the code to save the file doesn't get executed when I shut down/reboot windows.
Is there a way, probably thru' Win API to register my app with Windows, so that windows actually waits for my app to terminate in a sane way after saving the data. I remember of reading about this possibility somewhere, I don't remember now.
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May 27, 2012
How data is saved DataGridView after shutdown By Settings in vb.net 2008.This is an example for ListBox.I want an example of DataGridView..[code]
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Sep 22, 2009
I have a vb-2008 program that contains a (listview) control.
View = details
AllowColumnReorder = true
Lets say the table has 3 columns (a,b,c) and 1 row of data.
a b c
1 2 3
I want the user to be able to re-arrange the columns (by dragging the column headers) before printing the contents of the table.
c a b
3 1 2
Statements like:
.. ListViewX.Columns(2).Text
.. ListViewX.Columns.Item(2).Text
.. ListViewX.Items(0).SubItems(2).ToString
Give the column-name (c) and cell-contents (3) of the origional table .. not the (3rd) column (b) of the re-arranged table.
How can i get the column-name and cell-contents of the (3rd) column of the re-arranged table?
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Mar 20, 2010
i am developing a point of sales system. currently i have my product code scanned and displayed in a listview. lets say that i have 5 product codes displayed in my first listview. By clicking on a button, how can i use these codes to call upon the details (prices, product name, etc.) of the corresponding codes and display in another listview?
i am using Visual Basic 2008 and MsAccess as my database. who have the idea on solving my question. (As my last thread has not been answered at all..
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Mar 1, 2011
I have a datagridview in a form that is dynamically bound to a datatable. When the user clicks a button I update certian columns of the current row with code like this:
Dim i As Integer = myDataGridView.CurrentRow.Index
Me.myDataGridView.Item("closed", i).Value = DBNull.Value
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Mar 20, 2010
i am developing a point of sales system. currently i have my product code scanned and displayed in a listview. lets say that i have 5 product codes displayed in my first listview.
By clicking on a button, how can i use these codes to call upon the details (prices, product name, etc.) of the corresponding codes and display in another listview?
i am using Visual Basic 2008 and MsAccess as my database.
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May 1, 2009
I'm working with Visual Basic 2008 Express. My application opens with the Terms screen, a form that asks the user to declare his acceptance of certain terms and conditions or to decline. If he accepts, the app opens the main screen, giving him access to all the app's facilities. If he declines, the app gives him a message and then closes. Whether he chooses to accept or decline, the app puts his decision in My.Settings so that it can be used next time the app is opened. In this way he is presented with the Terms screen on the next opening if he declined on the last run. But if he accepted on the last run, he is presented with the main screen on his next opening.
All works fine when I do a debug run. But when I build and publish the app onto my desktop it opens with the Main screen instead of the Terms screen.
why it works on F5 but not after publishing?
Public
Class frmTerms
Dim Accept As Boolean
[Code].....
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Sep 4, 2009
I need to very quickly write an exe system on a laptop where when the laptops are connected to the network they read a database table and store the data locally, so staff can use the laptop while they roam.The laptops have quite small capacity and the company would prefer not to use SQL Express or Access.
My question is, can the data initially be downloaded into the exe application via a dataadapter and dataset, and will that dataset the retain the downloaded data, or will I need to ensure the dataset is written to an XML file and then loaded/unloaded each time the laptop application is started while the staff are travelling ?
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Jun 6, 2012
I am a web developer who now has to change a Windows service. I never worked on a Windows service before. I have a several programs that can run within this service. I want to persist a value of a variable from program to program.
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Mar 21, 2012
I'm having some problems in persisting the viewstate on postback for a Control (vb.net)
here's some code i've put in my control[code]...
I'm setting EnableViewState = "true" everywhere i can, but still no result. Do i really need to set those properties here. (ViewStateMode and EnableViewState) If not, where should i handle this and what is the difference between those properties?
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Dec 9, 2010
I have been searching for quite a while now but i am unable to find the answer to the following. I am storing a key pair in Windows Store, and recently started receiving the "Keyset does not exist" error. Investigating a bit further i found out it could be two things, 1 - The private key is not stored with the persist key set attribute (X509KeyStorageFlags.PersistKeySet) and 2 - access rights to the key. I have tried both 1 and 2 with no success on one machine (in my machine it works apparently). The strange thing is that when i look into MicrosoftCryptoRSAMachineKeys (and S-1-5-18) the key remains there but only for a period of time then it is deleted which means that it is not persisting.
//If decoded then save as RSACryptoServiceProvider
newCert.PrivateKey = DecodePrivateKey(privateKeyFile, pkPassword)
if (newCert.PrivateKey == null)
[Code]....
I have just found out today that since i am doing this through a WCF service, the application pool is deleting the private key when it reaches its idle time limit so i am completely sure that it is the application pool the one disposing of the private key which causes the key to be deleted from the MicrosoftCryptoRSAMachineKeys and S-1-5-18 folders. Today i left a test running where i disabled Idle time shut down from the application pool bu i am still not sure if the private key will stop persisting with a restart or something like that?
Would anybody know how to make the application pool stop deleting my private keys?
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Oct 10, 2011
I'm looking for a simple, efficient way to get the position of the browser vertical scrollbar and save it into a session variable in an ASP page. What I'm trying to do is when the user changes a page I've the scroll position stored in a session variable so that when the user returns to the page the page will scroll to their last position.Is there a way to do this? I've seen examples of persisting the scroll position on postback but nothing yet doing exactly what I'm trying to do [code]
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Jun 16, 2010
I need to save the controls location and size on the parent form to file. My aim is to be able to simply copy that file to the path where an instance of my program is running and then it automatically applies the previously saved layout of controls. How can I use My.Settings to do that or is there another better option?
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Apr 21, 2009
I am having a problem regarding to pass all the data on the listview from one form to another and add another columns. The purpose of my columns is that I want to put text from there because I am sending a mail but I want to get the status of my message if it failed or send and write it at every end of the rows.
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Jul 26, 2011
Sorry for the extra long title, Here's what I want to do.I want to give the user the option of using or not using specific features of the program.If I can set a simple yes or no value that wil persist each time the program run and then depending on the variable turn off or on the feature at start
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Jun 27, 2010
does anyone knwos what is the point of persist security info? i have always leave it at default (i'm not sure what value it is) but when i pass the application to my friend he seem not to be able to connect to the db. (btw the application calls
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Feb 12, 2010
Instinctively, I would say that this is impossible, as NHibernate needs to know some mapping information on how to persist a given type. Thus, I encountered some situations in which I could use such a feature. For instance, through a named query or something like so. On the other hand, using a named query would require me to make an addition to the configuration file.
Let's suppose we have an application interacting with some underlying datastore. This datastore is configured through the NHibernate configuration file. Then, I wish to have NHibernate load only a subset of an entity properties, from another subsystem to which my application shouldn't need to interact much, so it is not worthy to define classes for this system, as I only need a fraction of this alien system's information, let's say three out of thirty-two data columns. For that matter, if I chose to load only those three columns let's say for performance concerns, I would then use an anonymous type, perform the required action onto this information, then persist it back to the datastore. Now, it wouldn't be of much interest to do so if I only had one entity to get loaded from the datastore, so let's say I have about 75,000 rows to load into my process. I then shall consider this subset option very seriously!
What strategy should you choose in such situation, if you needed to persist these changes to a subset only of this entity's properties?FYI: I am asking because I must write specific rules of usage with NHibernate, such rules that even a beginner developer would even be able to use it without knowing too much about NHibernate, but only following the rules and guidance of the technical documents I have to produce.
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Apr 15, 2012
I am making some changes to a fairly old project.It has a DataGrid with an Inherited Class
Public Class CustomDataGridTextBox
Inherits DataGridTextBoxColumn
and a Override Sub Protected Overloads Overrides Sub Paint (.......What it was doing was alternating the Data Grid Line colours New Requirement is to break up some items in the DataGrid By categories So I have added new lines to the data and sorted so they show up ad category headers (Production Stations) And they would like the Category Header to be a different colour and then the alternating line colours to restart.This did not sound too difficult but that has proven a trap Setting the category header is no problem but restarting the alternating colours is Previously the row was determined to be odd or even to set the colour.Now I am intending to use an Integer to define what colour is used but it persists only for that text box.
How can I get it to extend its life so each call can refer to it and update it and set the desired colour?All I need to do is have an integer variable that will hold its value for the next call?
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Nov 11, 2009
I have an app where I need to dynamically choose an SQLDataSource for a GridView so I can use 1 of 2 stored procedures, depending on who is logged into the system. My problem is that I am using logic like this, in the button click...
If Session("SiteType") = "Type1" Then
GridView1.DataSourceID = "SqlDataSource2"
Else
[code]....
This happens when you click the button that reveals the panel with the gridview in it. The user then makes changes (basically adjusting a text box on one or more liens of the grid) and then clicks "save". However, the gridview no longer knows its DataSourceID once this happens, so when I try to go through the gridview's rows - there are none.
If, in the save button's click, I put the same code, it (of course) blanks out any of the data changes I made in the form. So, simply put - how do I dynamically choose the SqlDataSource, but only one time, so that the program then keeps that SqlDataSourceID associated with the gridview until the end of the cycle? Is this a ViewState thing? I don't totally understand ViewState...
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Mar 16, 2012
im using vb.net 2008 and i would like to ask if is it possible that if i click a data in my listview then it would go to another listview and using a db
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Aug 23, 2011
I'm using an Entity Framework context, and sometimes would like to create a transaction so that the client can do multiple changes and then commit/rollback them all together.However, if many changes were made, and SaveChanges() was called multiple times, after which a rollback is called, entities that were commited already, will remain the way they were commited, and would not roll back.Here's how my transaction-relative functions look like:
Public Sub BeginTransaction()
Dim context = HttpContext.Current.GetObjectContext()
If Not context.Connection.State = ConnectionState.Open Then
context.Connection.Open()
End If
[Code]...
Not only does the test fail, but it also leave the ObjectContext in an unstable mode, because it still has invalid changes in it.
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Feb 22, 2011
Modifying data with the ListView's EditItemTemplate by programmatically settings its DataSource property and calling its DataBind method. I don't have option to use data source control for ListView. All ListViews are bound with data from code-behind. So, I have to handle the Edit/Update mode of ListView manually. [Code]
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Apr 1, 2012
I have default.aspx used masterpage, in master page i have a control called DefaultMenuContent, this control have a dropdownlist with autopostback, the problem is loosing the selection even if i use Is Not PostBack in control's load event, how to persist the dropdownlist selection?
In Master:
<asp:ContentPlaceHolder ID="MenuContentPlaceHolder" runat="server">
<art:DefaultArabicMenu ID="DefaultMenuContent" runat="server" />
</asp:ContentPlaceHolder>
[code]....
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Aug 1, 2009
How to block shutdown using vb.net?
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Sep 13, 2010
Shutting down a pc in vb.net is easy:Process.Start("shutdown", "-s -t 00")less the user has locked the pc in which case the above fails.How do I get around this in vb.net? How do I shutdown a locked PC?
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Jun 11, 2010
I am making a program that takes a time input from the user or a countdown amount and when that time comes it will shutdown or restart or log off the computer. I know how to make the timing code and everything else but i don't know how to shutdown or restart or log off.
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Jun 11, 2011
I'm currently writing a small system tray app that needs to shutdown my PC at a certain time. That bit's easy:Process.Start("shutdown", "-s -t 00")But how do I do this when my PC is locked? The above doesn't work and I don't want to leave my PC unlocked and unattended
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Aug 2, 2009
I want to hear some discussion regarding what is the best way to persist program parameter and variable settings from one run of the program to the next. I used to often use the ubiquitous INI type file in VB6 programs but I am aware that these are not formally supported in .Net programs. I also have a major aversion to adding to the already overwhelming bloat of the Windows registry by using that to store values.
[Code]...
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