Database Application: Tracking And Responding To Changes In The Data?
Feb 2, 2012
I'm using VB 2010 Express with a local Access DB. On the form I have a DataSet, a TableAdapter, a BindingSource that points to the DataSet (and the DataMember is the same table as the TableAdapter), a BindingNavigator that points to the BindingSource and finally a DataGridView that points to the BindingSource also.
I have added a Save button to the BindingNavigator. I want to enable / disable the Save button depending on whether there are changes in the data to send back to the Access DB. I think this is the code, but I am not sure if I'm really doing what I think I am (i.e. I am concerned I will assume something turns out to be wrong) or if there are better ways.
I am also uncertain what event to use to respond to. I have guessed at CellLeave, but I could be wrong and there might be much better choices. Finally I've been told that it's different if it's a DataTable, but I do not know enough to determine when something is a DataTable?
Private Sub CompClass_DataGridView_CellLeave(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles CompClass_DataGridView.CellEnter
Me.BindingNavigatorSaveItem.Enabled = Me.Component_MI_DataSet.HasChanges
End Sub
I have a tracking device CT-04 car tracker that i am trying to integrate with my vb.net desktop application. I have the protocol from the manufacturer (redview) that contains the commands to send to the tracker unit and from tracker to the server. My application is in vb.net .
I wanted to know how i can send the commands from my vb application i.e can i still use vb.net to send these commands to the tracker through gprs?
what do i require in terms of hardware and software from my side in order to send these commands through gprs (not SMS ) to the tracker unit and to receive data from the unit.
Is it possible to create an application with vb.net to track a users usage of Excel, Word and another application called lets say - Userapp.exe
At work we have been asked to create a diary of our days work and since most of my work is in excel, word and a custom application I have built, I was wondering if it was possible to track the usage of these programs store the data in a datatable and then save it to a access db.
Usage of the program would mean the time that the file is open on the screen, that way the time a program is open but minimised in the taskbar would not be counted.
The data table would have these headings -
1. Program (i.e excel, word etc.) 2. Name of File used 3. Time used in program
this is my first post and my knowledge of Visual Basic is still in its infancy (this is my first real attempt at app that is any use) however I am trying to develop an application to delete user profile and home directory folders.
I have the application working but the problem is with the application hanging (I understand this to be due to it running as a single thread and the main form gets ignored while the deletion is occuring) during the deletion process, I have tried various ways to resolve this such as starting the delete procedure as a new thread but cant get it to work without the hang.
My mdi VB.Net application performs a long operation on some data. Ideally I should use a separate thread to prevent the dreaded "Not Responding" message.My problem is if I use a separate thread users then have the ability to click on other controls in the application which can directly affect the operation my background thread is working on, creating an error.
Is there any way to prevent all the mdi windows, toolbars and other controls from receiving mouse clicks and keyboard input during my background thread's operation?
Or is there a way to clear the message que before performing a Application.DoEvents?
I can pause the application and see that it thinks no threads are running so no call stack. The other projects in the same solution are all responding fine, just this one stalls. I can not think of any way to work out what it was doing at time of stall, I have no event logs, no breakpoints, there is no particular thing I can check for in my own logging system (which is quite extensive) that shows where/why/what the application is hanging for. Any clues on how to solve/investigate? To add, this is on a Vista box, but not able to move the system to anything else (source controlled) until I can find out what this is. Its an avenue I can go down if required however.
Im building an application in vb 2010 which uses window media player component. When I run the application in debug mode and Press Play button, the application hangs up and stops responding. When I press PAUSE button in vb 2010 the line it shows is
When starting my application, I have a couple of classes which are required to read certain files in order to create a set of default data. The logical place (to me) to do this is in a Shared class constructor; the idea would be to throw a class-level event if the reading of the defaults file fails. Unfortunately, this does not work as attempting to access such an event, in order to attach a handler to it, fires the class constructor before the event has been attached. In a failing case, the constructor starts, fires the fail event, the constructor completes, and then the event handler is attached, after the event has fired.
The only other solution I can think of is to give the class a "typeInitialisedSuccessfully" boolean property and put a try/catch block around every call to construct an instance of the class, which seems unnecessarily kludgey to me. Can someone suggest a more elegant solution?
EDIT: Because this is a fundamental Class, used in one form or another across nearly all of our software tools, I would greatly prefer a solution that will notify future programmers that the type initialiser needs to be called, which is why I initially went towards the Shared Constructor as a solution.
In my application, the user can create a word document from a word template with dynamically added text and data to it. This happens on a backgroundworker so that the application doesn't hang during the process. This all works fine and the word document opens correctly when finished. Now if the user leaves the application to do something else, in most cases when they come back to it, it has frozen. It's still responding/running in task manager but the interface is frozen. In debug mode, it never freezes and so I can't catch the exact moment when the freeze occurs. My backgroundworker is disposed of when complete and I close everything related to the word object.
I'm uploading an image to url... etc. The trouble is my application stops responding for 5-10 seconds while the image is uploading. I want to use multi-threading to stop it doing that but I'm confused with the whole way to use controls with backgroundworker. [code] I guess its the textbox which is causing the problem.
I am trying to search for the occurence of a string within MS Access database with 1000000 records using VB.Net. The program does not respond once it is run or it is taking a very long time. However, if I reduce the size of the database the program runs.[code]...
I have created a little program that helps me keep track of tons of data by inserting it into sql. I created 5 forms and all 5 can insert data at the same time, but mostly just 1 of these is working continuously. I have noticed that the program will run, then at random times it will stop responding (can't minimize/click on anything/data entry stops), and the only way to stop is to kill the task. I can't even click in the debugger to set a break point when it happens, and setting breakpoints before debugging is useless as the program could run 2 hours and stop, or 10 minutes and stop. 5 forms, they open different excel files, insert data into sql, and repeat.
I have created several WPF User Controls. The lowest level item is 'PostItNote.xaml'. Next, I have a 'NotesGroup.xaml' file that has an ItemsControl bound to a List of PostItNotes. Above that, I have a 'ProgrammerControl.xaml' file. Each ProgrammerControl has a grid with four different NotesGroup user controls on it (and each NotesGroup contains 0-many PostItNotes.
Then, I have my main window. It also has an ItemsControl, bound to a list of Programmers.
So, you end up with a high level visual view of a list of programmers, each programmer has four groups of tickets, each group of tickets has many PostItNotes.
The trouble I'm having, is that I want to respond to a mouse click event in my mainWindow's code behind file.
I can add a MouseClick event into my PostItNote.xaml.vb file and that is getting called when the user clicks a PostItNote, and I can re-raise the event; but I can't seem to get the NotesGroup to listen for that event. I'm not sure if that's even the correct approach.
When the user clicks the PostItNote, I'm going to do a bunch of business-logic type stuff that the PostItNote control doesn't have a reference to/doesn't know about it.
I have a data logging application that stores data in a table in a MySQL database. Data with a TimeStamp is logged into the table anytime the data from the sensor changes. This means that there maybe 2 seconds between data points or there maybe 20 seconds between points depending on how the data is changing.
When I need the data I have 2 dates and use this command to fill a table..SELECT FROM myTable WHERE timeStamp > date1 AND timeStamp < date2 This gets all the data that has a TimeStamp between the given dates, but in most case the first date in the returned table will be after date1, so I need to get the data from one row before the date returned in the table to know what the data was at date1.How can I get the data row that immediately precedes the returned data set?
I am using FileCopy and My.Computer.FileSystem.CopyDirectory to copy certain files and folders. The problem I have is that when this operation is being carried out for a large directory (say 1gb or so, probably less) - the program goes into a Not Responding mode until the copying is complete. If you let it sit there, it will eventually resume itself once the copy is complete; however, my end user is going to think the program crashed.
i m trying to write codes for new user to fill in the form, then the new data will into my database,however, my codes doesnt work, i cant figure out what's wrong with my codes. below are my codes:
Imports System.Data.OleDb Public Class NewUser Inherits System.Web.UI.Page
[Code].....
there is no error encounter, however,the adding is failed and no new data can be add in.
I have an application half built which accesses a Access (2003)Database File. From within the application I am able to change the data in the Access File using a Data Grid. The changes to the Data File are saved and can be recalled, changed or otherwisemanipulated however, when I add too or change any of the applicationcode the Access file reverts back to it's original state losing any data or changes that has been made.
I am designing a desktop application that will be driven by local data. I am trying to determine the best way to accomplish this. The database would contain about 10-12 tables if I use a database and I would imagine no more than 10000 records in any one table (but honestly 99% of users would not have more than 1000 records). I am thinking about using SQL Server Compact.
Is this a good solution? I can certainly include this in my installation, but I am just wondering if anyone knows of a better solution? If this is the best solution, how would you suggest that I create the tables upon deployment? Should I just run "queries" with create table statements in them from my vb application or include a database file or what?
i am just developing a library management system as one of my project. i using vb.net 2010 and the MS Access 2007 as back end. when i save some records into my database through my application it is correctly saved and i confirmed it through opening the relevant table in the database. but when i restart the application all the entered data were missing.
I have created an windows application which stores it data in a database. What I would like to know is how do I access the tables in the dataqbase and transfer the data in them into textboxes on the forms in my application. I can connect to the database and view the tables, but I have'nt got any idea how to get the data from the fields in the tables into the appropriate textboes on the application forms.
I have a checkbox in my application,when the checkbox is checked then i want to fetch the data from the database and add it to the dropdownlist of the combobox.Again when the checkbox is unchecked then i want to ramove all the data from the dropdownlist of the combobox.
I did this
Private Sub CheckBox1_CheckedChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles CheckBox1.CheckedChanged If CheckBox1.Checked = True Then con = New OleDbConnection("Provider=Microsoft.Jet.Oledb.4.0;Data Source=Etech.mdb")
[CODE]...
When the checkbox is checked then the data is added from the database to the dropdownlist of the combobox but when i uncheck it then the data is not removed from the dropdownlist of the combobox. In the above code i think i need to add an else condition to remove the data from the dropdownlist of the combobox and make it empty when the checkbox is unchecked.......but i cant give the proper else condition in the above code.
The fact is I'm making an application, which users can install by using a Setup file...once installed the data in the database can be updated by a centralized server. To do this, they can insert a DVD/CD-ROM and export the necessary data towards it. I need to do it that way, because some of the users who really need this data will be using stand alone computers.The application gets it's data from a mdb-file and the connection remains open as long a person works with the application (maybe not the best way to do, but I know :-) )...when the user uses the application, he can perform an export...this exports the .ini-file and pictures (which works fine), but he also needs to export the mdb behind the application...I already tried connection.close() before and connection.open() after the System.IO.File.Copy...but that doesn't seems to work.
I got a system which i want to insert, delete, update the data into my database and the data from database will be display using datagrid. The below is the coding for one of my button, delete.
Private Sub btnDelete_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDelete.Click Try btnSearchEmpNo.Enabled = False[code].....
Now I wanna set when user click on this button to delete a employee (for example) then the datagrid that i have in my application will not show the data of the deleted employee but in the background, the employee haven't been deleted from database.The employee only will be deleted from database when the user click on SAVE button.I know this application have to use RowState but how?
What I want to happen is that the button from my system will remove the previous data from database and then insert new data to database from text file. Im done with inserting new data. The thing is that I dont how to control or where to put the Delete Command from my code.
Thought I would put this out there before I embark on my own research. In a current MVC 4 app, I am looking for a way to track/audit visitors. I am looking for a way to: Record a record on each site request. Record will include things like logged in user, session id, requested page, page coming from, etc., etc. Action methods will be decorated with an attribute to trigger the creation of that record, so we can specify exactly which action methods get logged.
On a project I'm building for a client, one of the requirements is advanced user tracking. The client would like to know what pages an authenticated user is visiting, and when. I read through this post, which is probably the method I will go with. However, that seems a bit tolling on the database, and being that the client may use Azure to host this, I would like to keep the # of db transactions to a minimum [although this was not one of his requirements.. Anyway, I'm torn between the following two methods..
Method One: Log to db on every HTTP request using a HTTP module Method Two: Store in visits in session and log everything to database in one swoop during Session_End event
