Detect That Data Has Changed On Database?
Oct 28, 2010
'm developing multi user systems where for example I could have a form with a list of users on it. If a user on another system adds a user then I would ideally like for the new user to show up on my list reasonably soon. While that could be done by getting refreshing the list every couple of seconds I would prefer to be able to identify that a change has happened and then be able to decide what to do from there (whether that be actually refresh the list or inform the user that a change has happened and ask them what to do).
The only way that I can think of doing this is to store the information that was originally retrieved and then every x number of seconds requery the database and then compare the two sets of data, if there are differences then raise an event.
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Oct 26, 2011
I want to track changes in an application. So I've made a copy of the main table in that application, and am accessing both tables in the application using two separate datasets.
My plan was to use the HasChanges method of the main DataSet to get changed rows and then insert those into the copy table. When I run the code I get an error:
A first chance exception of type 'System.InvalidCastException' occurred in MyApp.exe
Unable to cast object of type 'MainDataTable' to type 'MainAuditDataTable'.
Here's the code:
If Me.DataSet3.HasChanges Then
' 'look for each row that has changes, not new rows
' 'insert that row into the auditing table
[Code].....
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Jan 20, 2010
on my Form I have a DataViewGrid and some textboxes with a save button (they are filled with additional data of the selected row).Save is disabled first, when I change something in the textboxes the save button is enabled.When the user changes a gow in the grid, I want to ask before changing the grid row, if he wants to save (if the button is enabled).I am using RowEnter but this is too late, then the selected row already changed (and my textboxes already got new data)...What event can I use to ask if I should save stuff before the user changes a row?Something like BeforeRowChanging with a chance to cancel changing the row?
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Feb 20, 2011
I've finally cracked how to detect that Form1's size has changed?[code]Now I have another problem, my intention was to adjust the font sizes of some labels, buttons and textboxes to reflect the change in form1's size.I find that font size is Read only, so I thought OK then, I'll adjust the Bold: Wrong! bold is also Read only.Ideally I'd like to leave the bold on and adjust the character size.The controls all change size correctly within the minimum width and height restrictions of the form, but sadly, the larger some controls get their texts start to look like a pea on a drum.
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Feb 26, 2011
I want to detect when the user has changed the content of a Textbox.
The following does not work for me, because: When the user navigates through the database (using my navigation buttons), the textbox is also changed, but NOT by the user making input. I would only like to know when the user EDITED the Textbox.
Private Sub mskStudentNumber_TextChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles mskStudentNumber.TextChanged
If Not Movement Then '' If not navigation
[Code]....
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May 17, 2012
I'm developing a VB.NET application that is going to be checking if a table has been changed and if it has get the data and send it off to another application.
I was looking into ways for an application to know that there has been new data added to the database (Insert/update) or removed from the database (delete). There are only two methods that I found the first is querying the database constantly but this isn't very scalable and would probably take down our sever. The second approach is via a Query Notification but it seems that this is only do able with SQL Server 2005 and we use DB2 here.
My question is what is an efficient scalable method of checking for new data in a database that can be implemented using a DB2 database and VB.NET?
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Feb 28, 2011
I have some textboxes bound to a bindingsource and bindingnavigator.
I want to detect when the values have changed and prompt the users to confrim if they want to update.
When the form is first initalised and when then binding navigator moves to the next record the text_changed event fires on textbox where I have a boolean to determine if things have changed.
Is there a way to set my boolean only when valid data changes have occured or a better way to detect if things have changed
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May 5, 2012
I changed my Username on my computer from i.e. "xxxxxx x xxxxx" to "Dennis"
VB 2008 during a compile gave me the following error: Error reading icon 'C:Usersxxxxxx x xxxxxAppDataRoamingMicrosoftVBExpress9.0VSProjectApplication.ico' -- The system cannot find the path specified.
The file "VSProjectApplication.ico" is in 'C:UsersDennisAppDataRoamingMicrosoftVBExpress9.0'
Somewhere in the VB2008 "configuration" files I believe that I need to manually change the old path to the new path.
I found the old path in the ".suo" file. The ".suo" file is not a text file. How can I edit the .suo file, save it so that it will work?
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Dec 16, 2011
Ok, I have been going around and around with this for hours (Searching, etc). This is what I want to do, I want to load data into a Text Box and if the user changes the text in the Text Box I want to be able to save the new text.
My problem in the TxtBox_TextChanged event the data contained in the txtNarrative Text box is the new data that the user typed in (<>ABCD) but in the btnSubmit_Click event the data contained in txtNarrative is the original value ABCD.
<%@ Page Language="vb" AutoEventWireup="false" CodeBehind="Default.aspx.vb" Inherits="WorkBench_VBNet._Default" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
[Code]....
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Aug 4, 2011
On my form with my detailed layout of my database in textboxes i can change my data or add new record.
how can i verify if there was any changes to a record when the form is being closed or when my cancel button is pressed.
i want to create a message box that warns tha there hav been changes made should it be saved yes or no
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Jan 5, 2010
I want to edit values in datagrid in VB.NET and also want to save changed value in database. How can i do it?
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Mar 3, 2009
I have a form that builds and populates dynamic text boxes from parsing a file. There is a "Last Name" text box that when populated, also labels a tab page with the name. After the form is populated, the user can change data as they desire but I was wondering how to update the tab page text when the user updates the last name text box? All the controls are built in code.
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Nov 10, 2010
I am trying to migrate from Access Database to SQL server database. Do I need to make changes (for saving, reading, deleting etc. data) to my code as well?
I understand I need to change connection but what about code?
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Dec 22, 2011
Im Trying to create a NotifyIcon Program. I want this to basically be like a service that every second looks at a database to see if anything has changed this is the module thus far
Imports System.Data.OleDb
Module ModNtifi
Public conn As New OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=\MyserverMyDatabase.accdb ;Persist Security Info=False")
[CODE]...
The Problem i am getting is that after the start procedure has finished the program closes. i want it to start the the timer and then keep it going till the user exits the program manually.
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Aug 3, 2011
I am retrieving data from my database using a TableAdapter. I was wondering if there is some way I can tell (or be informed) that the data has changed and I therefore need to do another Fill? That way I can just Fill on demand rather than every time the user requests to see the information and I am forced to do a Fill before showing the data because I don't know if is current or not. For the record I am using an ODBC connection string to access a Pervasive PSQL database
EDIT I was thinking I could check the last write time of the MKD file to check if this has changed but this doesn't seem to be reliable as it is not written to until the connection is closed. Does anyone know the circumstances when this is written?
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Oct 5, 2009
A quick question on caching dataset objects. How can I know if the data is changed in Sql when caching data? I don't want to specify time constraints but used a strategy where data is changed in sql and I have to refresh my cache?
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Apr 29, 2009
Im using VB.NET 2008
I know I can exit a program by using the End statement.
But i was wanting to know how to check to see if the data has been changed since it was loaded and bring up a diaglog box up saying the data has been changed or not saved, would you like to save the data before exiting?
I will have a form that will have a yes, no, and cancel buttons.
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Apr 29, 2009
Im using VB.NET 2008 I know I can exit a program by using the End statement.But i was wanting to know how to check to see if the data has been changed since it was loaded and bring up a diaglog box up saying the data has been changed or not saved, would you like to save the data before exiting?
I will have a form that will have a yes, no, and cancel buttons.
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Jun 12, 2012
I am trying to get my grid to refresh automatically when the underlying data is updated in the database. Isn't this supposed to work? Or am I missing something? I created a DataTable within my DataSet. Then I created a new form and added a DataGridView (actually I'm using DevExpress' XtraGrid but am trying to get it to work with just the Microsoft controls). I use the menu in the upper left of the grid to set the grid datasource to the datatable in the project data source. This then automatically adds the dataset, BindingSource, and TableAdapter to the form.
[Code]...
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Mar 23, 2012
I have been trying to do this for ages and having no joy whatsoever.
I have a ribbon window of the following hierarchy:
MainWindow
MainContent (Tab Control)
TabContainerViewModel
ViewModelBase
View model base has an ObservableCollection of tabs type ViewModelBase. The Tab Control itself is binding fine to these, displaying appropriate view models. I have 2 problems however, I want a "NotepadView" (Of type viewmodelbase) to be replicated numerous times (one view many view models).
At the minute, I have 4 views (NotePadViewModelx where x is 1-4) with corresponding viewmodels, this is because each view had the same text per tab. Now I have individual views per tab.
When I type into tab 1 and switch to tab 2, I lose what I typed in tab one when I click back.
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Jan 16, 2009
I have a WinForms app with a datagridview and a bindingsource. I want the user to confirm changes before I save them to the database. don't want to pop up the confirmation dialog unless I know the user has made changes. So I need a way to check if changes have been made.
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Sep 22, 2009
I got a DATASource connected, changed the table to details and draged it on to my form, but then it shows me the bindingnavigator at to of my form.
q1. how do i make it so every time this form opens it is like add new?
q2. how do make my own save button (don't want the binding navigator at top)
q3. in my form all my collums aper as textboxes how can i change it so there is a drop down menue that has forexaple 3 pre defined items that the user has to select on of.
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Mar 20, 2011
In vb.net using Data Reader while selecting an value in combobox should display an selected value record from the database into textbox.
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Jul 30, 2009
I have a class that contains a collection of another class. See below
Public Class Spot
Private mActive As Boolean
Public Sub New()
[Code]....
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Feb 18, 2011
Moved from Microsoft Developer Network
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Windows Debugging
[Code].....
MS has a patch for the OnListChanged event handler issue, even though it seems we have to pay to have access to it. This fix specifically addresses an error message when you press ESC to cancel adding a new row in .NET 2.0: [URL]
FIX: Error message when you try to press ESC to cancel adding a new row to a DataGridView control in the .NET Framework 2.0: "An unhandled exception of type 'System.InvalidOperationException' occurred in System.Windows.Forms.dll"
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Sep 26, 2011
Our database has been having some occasional troubles and this seems to be presenting a problem in my new app. How should I test to make sure the database is up before sending SQL statements to it? We are using Oracle 11g and I am using odp drivers, VB.net 2010, .net framework 4.0.
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Sep 12, 2009
I am currently having trouble detecting the number of rows in the table in sql database. I have one column as auto increment, and one column that will show the blkname. But everytime I delete off one row, the program cannot run saying that there is no row at position "up to the latest number". Then, when I try to insert back the row again, the program also gives me the same error. I think the program probably cannot detect the number of rows correctly as it cannot like detect if there is 5 rows in the database and if you delete one row, it will give me the error. The above method is the same if I used the auto increament column and without.
The code that I have wrote so far is :
'AUTOINCREMENT
Dim n As Integer
Dim inc As Integer
Dim numbers() As Integer
Dim StartFrom As Integer
Dim EndAt As Integer
Dim MaxRows As Integer
MaxRows = ds2.Tables("CustDetail").Rows.Count
[Code] .....
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Apr 4, 2012
i have here a code for my back up:
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim dbload As String = Application.StartupPath + "\Enrollment System.accdb"
[code]......
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Mar 28, 2010
I have some Crystal Reports connecting to a Sql Server db that I would like to detect whether the connection is trusted or whether I need to supply the log on info (reports are not supplied by me so I can't control the connect method). If I just blindly supply login credentials, it won't connect if it is a trusted connection.The following does not work:
oRpt = oCR.OpenReport("C:MyReport.rpt")
if oRpt.Database.Tables(1).ConnectionProperties.Item("Integrated Security") = True then
'trusted connection[code]....
It gives the following error:Operator '=' is not defined for type 'IConnectionProperty' and type 'Boolean'.
I cannot find how create a construct in vb.net for IConnectionProperty. I can't find any documents from Crystal that explain it.I am using Crystal Reports XI - Developer
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Aug 10, 2010
Is there a way to detect when the Tab key is pressed?
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