Why Vb Is Called Event Driven Programming

Feb 9, 2010

event driven programming


What Is An Event Driven Application

Jan 21, 2009

What is a event driven application.

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Event Driven Tcp Listener Method?

Aug 23, 2011

I'm another newbie with VB (2010) so please bear with me.  I am attempting to make a method that is event driven by data threads on the Ethernet port.   Simply put, the method is to wait until a data thread from a "Control By Web" 5-input device sends an "information update" data packet to the application, with the application then processing the information.  This application is on a private, well controlled network, with no access to the internet.  I have a method that is working right now reading data packets when invoked with a timer (see code below) but I really need it to be event driven.

' this is added at the top of the class
Dim tcplistener As New TcpListener(IPAddress.Any, ip_port)
'this is added in the "form1_load" module


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VS 2010 'Public Event OnFilterAdded()' Is An Event, And Cannot Be Called Directly

Dec 25, 2011

what is the error in the bleow: 'Public Event OnFilterAdded()' is an event, and cannot be called directly. Use a 'RaiseEvent' statement to raise an event. Note: the error line is italic underline

Imports System
Imports System.Collections
Imports System.Configuration


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Game Programming :: Have An String Array Called ArrMap (0 To 19) That Holds The 20 Rows Of Each Map For Display?

Sep 30, 2009

Im working on a roguelike console RPG. For those of you that dont know, just google search it.What I need help with is that I have an string array called ArrMap(0 to 19) that holds the 20 rows of each map for display. I also have an array of the same size called VisibleMap that needs to hold which portions of the map are visible and which arent so that when the player switches screens [IE goes from map, to inventory] they can go back to the map and it will look the same. I was thinking of using an array, but if you can think of another way to do it, that's fine.Here are the subs that deal with the map reading and display, so you know how I have things set up at the moment.

Public Sub ReadMap(ByVal location As String)
Dim ioFile As New StreamReader(location)
Dim ioLine As String
Dim intX As Integer


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.net - Event Handler Is Never Called Because The Original Event Is Raised In Another Event Handler?

Apr 18, 2011

The event handlers in my parent class are never called though the events are raised in the child class.

The Code:

Public Class childForm
Public Event checkboxchangedEvent(ByVal checkbox1 As Boolean, ByVal checkbox2 As Boolean)
Private Sub checkboxchanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CheckBox1.CheckedChanged, CheckBox2.CheckedChanged


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.net - BackGroundWorker RunWorkerCompleted Event Not Called Sometimes?

Feb 1, 2012

I'm seeing some strange behavior where the RunWorkerCompleted event for one of two threads I start isn't being called depending on how I call them. Check out the code below, and the two methods of firing the threads, good() and bad().


In both cases the DoWork event is called for both threads. But in the bad() case, only the second thread fires the RunWorkerCompleted event. This is obviously due to the two different ways I'm using VB to handle events here. I'm looking for an explanation of this behavior, preferably with a link to some documentation that could help me understand how these events are being handled in VB better. It seems strange to me that just reusing a variable name here seems to either dispose of the thread before it's done or else just make it stop firing events.

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Event Handler Is Not Getting Called After Click?

Oct 12, 2010

What is an "EASI" LinkButton? Why don't you just use an ASP.NET LinkButton? Try modifying your JavaScript method so that it returns "true" if you want the postback to occur...and "false" if you want it to stop. Then change the LinkButton to so that it "returns" the value that is returned by the JavaScript method... This should stop the postback from occurring (but then again I've nevers een an EASI LinkButton before.......)

<EASI:LinkButton ID="btnSearch" runat="server" CausesValidation="False" ClientScript="return confirmSearchOK();"UseSecurityLevel="True">Search</EASI:LinkButton> JavaScript modification suggestion:
function confirmSearchOK() { var planSel = document.getElementById("<%= ddlPlanID.ClientID %>").selectedIndex;
[Code] .....

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Form's Load Event Not Called?

Apr 25, 2011

I was having a problem with the debugger not stopping at breakpoints. After a lot of work that yielded no results, I realized that the problem was occuring in the form's load event and subs called from that event.

The problem is that it appears that the load event is not being called. Other startup forms in other projects in the solution seem to be working ok.

what could be keeping the the Load event from working?

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Forms :: Event Called On Load

Jan 13, 2010

I got a combobox, that when the texted is changed, its supposed to run a query to update a field in my database. Here is the issue The event im using is TextChanged, well unfortunately when the page loads, it changes the text when populating the values. Is there a way to make this event wait to fire until after the list is populated? Ive ran into this problem before with datetimepickers, but I was able to offset it with a boolean, but this combobox is calling the textchanged event everytime it adds an item to the list.

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Programming Paradigm Called OOP - To Be An Object Or Not To Be An Object ?

Feb 25, 2012

I am in the process of learning this new programming paradigm called OOP (I am a very seasoned structured programmer). In that context I am receiving what I call contradictions in vb.net regarding the instantiation of an object. Given the two lines of code below:

Dim SQLcmd As New SqlCommand
Dim SQLdr As SqlDataReader

The first line is quite simple - SQLcmd is an object - period. It is the second line that is creating the ambiguity. One reference I have read says in order for a class to instantiate an object the key word "new" must be used. But I have also seen examples where SQLdr is also called an object? To add to the ambiguity I have seen class examples where the class was constructed without a new subroutine (a constructor) and called with the key word "new" which I have been informed by vb.net on more than one occasion in doing such that "there are no constructors" in the class. So would someone please tell me - Is SQLdr an object and if so is it by inheritance (the other escape path) or what; and lastly am I correct in my understanding that in order to use the key word "new" there must be a "new" subroutine/function/constructor in the class.

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In Outlook 2010, ComboBox_AfterUpdate() Event Never Called?

Sep 20, 2011

so here's what happeningServer: Exchange 2010Client: Outlook 2010I've developed a custom form for Outlook 2010.in the form, I've added 2 fields:- ComboBox1 with the following values: value1 ; value2 ; value3- textBox1What I need is if someone change the value of ComboBox1, the TextBox1 will be populated with "You've chosen the value_of_ComboBox1".but I can't make the event to pick up!The msgbox never called.

Case "value2"
Case "value3"


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Timer Event Is Not Generated When C Dll Function Is Called

May 14, 2012

Net_mang_Form.Prg_bar.Visible = True
Net_mang_Form.Prg_bar.Value = 0


Here Net_mang_Form is Form1 and this code is written in button click event of Form2.

file_send is the function of dll .

prg_Timer is the timer control .

Prg_bar is Progress bar control.

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Asp.net - What Event Is Called When A .ascx Control Is Set To Visible / How Can It Be Handled

Jul 20, 2009

If I set a .ascx control's visible attribute to true, what event is called? What method can I create in that control's codebehind to act on this event?

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C# - User Control Button Click Event Called Again When Page Is Refreshed Using F5

May 26, 2010

I found that if you press F5 or refress from browser window, the last event fires again
example, I have clicked on a button, the button event is carried out normally, but if I refresh the page by pressing F5 key the same event is fired again.

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Game Programming :: Use Mouse Hover Event For Getting The Same Image Back After Hovering?

Nov 20, 2009

I am using VB 2008 Express. I am creating minesweeper game with picture boxes. I want a box in the grid to glow & I have created Different images form that. I want that whenever we hover over the box , it glows & I have used the visible property. I have set the property as false of all the glow boxes.


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Have A Column In The Datatable Called Amount And A Textbox Acting As The Filter Called Say Maxamount To Set It?

Feb 9, 2011

i was wondering if it possible to have a condition where lets say you have a column in the datatable called amount and a textbox acting as the filter called say maxamount to set it so the rowfilter when filtering the table will sum the number in the amount column until the number in maxamount is met, then stop and only return the rows where the total sum of the amount column is equal or less than the maxamount value, so i guess if the next row takes us over the maxamount it discards this row and returns the rows previous to it. is this possible using datagridview rowfilter or should i be loooking elsewhere to achieve this?

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Combo - Sql Table Called Stock With Two Fields Called StockID And StockCode

Jun 5, 2011

I have an sql table called Stock with two fields called StockID and StockCode. I want the user to select the stockcode from a combo which in turn populates the stockid for that item into a lable on my form. I have already populated the stockcode into the combo but dont know how to compelte the rest.

Imports System.Data.SqlClient

Public Class cbo2
Private Sub cbo2_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load


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Form Called FrmPracDetails Which Is Built Up With A List View Called LvwColProc

Aug 11, 2009

I have a form called FrmPracDetails which is built up with a List view called LvwColProc. Therefore when you click a field on the LvwColProc it takes you to another form called FrmColProcessing, here you can make changes to certain fields which are also present on FrmPracDetails. What I want to do is when you make changes on FrmColProcesing and Click the Save Button (which calls the Save function)the changes appear instantly on FrmPracDetails. Please note, FrmColProcessing will always be open next to FrmPracDetails. I have tried to put this code in the Save function present in FrmCol Processing as shown below, but it doesnt Refresh FrmPracDetails form. [code]

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Properties - Default Property Set Being Called Mysteriously Called?

Apr 2, 2012

I have the following line of code in my program:


This JCL_History object is basically a Generic.List encapsulated in a wrapper and has the following method:

Public Sub Enqueue(ByRef value As String)
If Members.Contains(value) Then


In my testing I have 2 items in this JCL_History list. When I call that first line of code I posted (the one that invokes Enqueue) with I = 1 I expect the first item to be shuffled to the bottom and the second item to be shuffled to the top.

After the thread returns from Enqueue I notice that this is exactly what happens to my list, HOWEVER if I hit the "step_in" button after the execution of Enqueue I go into the Default Property's set method where Index = 1 and value = and it screws everything up, because the item that got shuffled to the end (index 1) gets overwritten by the item value shuffled to the top.

So basically the set method on the default property is getting called at what I think to be a completely ridiculous time. What gives? By the way I'm running VS2005 on XP.

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Create A Custom Control With An Event Called "valuechanged"?

May 27, 2011

I have created a custom control with an event called "valuechanged"  When I try the following line to: AddHandler


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Mouseevent :: Mouse.Enter And Mouse.Leave Both Called In Same Event?

Jun 19, 2012

In my VB.Net forms application, I have a function:

Private Sub pnlMain_MouseLeave(sender As Object, e As System.EventArgs) Handles pnlMain.MouseLeave


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C# - Find Out If The "TextChanged" Event Is Fired If User Is Typing Into A Textbox Or MyTextBox.Text Is Called Programmatically?

Mar 9, 2012

Is there a way to find out if the "TextChanged" event is fired because the user is typing into a textbox or the programmer called myTextBox.Text = "something"? I don't want to react when the user is typing each letter into the textbox so I am using the "Validated" event to catch when the user is done so I can react. The problem is I don't have a way to catch when the programmer does "myTextbox.Text = "something". The only way I know to catch changes there is to use TextChanged but then I don't want to be reacting when the user is typing each letter into the textbox.

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VS 2005 Event Is Lost When A Second Form Is Called From The First Form

Dec 31, 2009

I have two forms. Form1 and Form2. The user is supposed to fill out some information in form2 which then will be used to compute some data in form1. However when I used the code, Form2.Show, within a function in form1, the form2 is diplayed but when the user fills the data and submits them using the ok button, the code does not return back to the function in Form1.

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Dynamic Database Driven Menus

Nov 15, 2009

I'm trying to construct a database driven VB.Net app that pulls a list of registered accounts from a database and displays the usernames of throes accounts in menu, so the user can select one and a new form open (where they work with it).what I have so far is the constructor for the MDI parent window.[code]What I want to happen is when a user clicks on the context menu a new MDI child form is created and the data in user is passed, however because AddressOf doesn't like passing data this doesn't work.I've looked at delegates and landa expressions but don't think either of them do what I need, the other option is to make my own subclass of the ContextMenuStrip class, which 1) handles the clicks the way I want to and 2) sounds like a nightmare.Before I launch into what I think will be a hell of a lot of work, am I missing something? is their a simple way to do what I want to do? or if not will sub-classing ContextMenuStrip work and if not any ideas as to what will (and if it will, any ideas as to how to start learning how to do that)

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VS 2008 Database Driven Application?

Jan 22, 2010

So. I'm making a tool for an online game called Shin Megami Tensei.In this game you can fuse Demons, depending on what family of the first demon you fuse and the second demon you fuse come from, and their levels, the outcome changes.This is unimportant though.

However, the application is driven by a database, the application consists of a Demonic Compendium (Index of the demons, including race, family, stats, levels etc.).This application is meant for usage by the community playing SMT, and here is the problem; a person without Microsoft SQL Server cannot run this application.I can't ask the community, some of which aren't very techy, to install Microsoft SQL Server 2005 Express Edition just in order to run this program.

You see my problem?Is there a way to get the program running on other computers that doesn't have MS SQL Server installed?

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.net - SSRS Report Called From ReportViewer Control Displays No Data In The Report When Called With A Parameter

Apr 11, 2012

Can you look at my coding and let me know what I'm missing or doing wrong?I have a SSRS report that is called from a ReportViewer control and the ProcessingMode for this control is Remote. The report also has 1 parameter in it's DataSet.In the code I placed a MsgBox to make sure the code is finding the parameter and returning the parameter name. I am trying to stick the value of 10 into the parameter for playerID 10. Data for this player does exist.

I believe I need to add some more code to make this work but I'm not sure what else to add.

When the code executes the report is displayed but no data is shown in the report.


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Office Automation :: Called "Freemind" That Is Called A 'mind Mapping' Program?

May 13, 2010

I recently found an awesome tool called "Freemind" that is called a 'mind mapping' program. It's similar to MS Visio but way cooler and more automated.I reeeallly would like to integrate this into a VB.net Form, but how?

Has anyone seen or heard of mind mapping inside VB.net before? Are there programs out there already that work with VB.net or anyone have an example they have seen / built that works?

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Data Driven Class/Property Reference?

Feb 17, 2010

I am trying to build a dynamic validator for a data entry application. I want to be able to query a table for the validators relating to the current task and then be able to reference class properties based on the description of the validators returned.

ex. Validator = "person/firstname"

How do I get to _clsPerson.FirstName?

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Date Driven App - Object Binding Or DataSet

Jan 31, 2010

I'm new to programming and am trying to learn how to developed data driven application and was wondering which method is recommended? I know there are some debates out there but most of the books I have recommend using object binding, but it doesn't offer any concrete information on how to implement it. I went to MSDN and most, if not all, the documentations are on dataset. So I guess my questions is, object vs dataset, which do you use?

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Deploy Database Driven Application Developed Using .NET?

Sep 2, 2010

I have developed a windows application which performs a series of database operations like select, insert, update. I am connecting to Oracle database and its working fine in development system. But, when I deployed this application, I am getting error at StartConnection (which opens the DB connection). After installing OracleClient in client system, its working fine. Now, my question is that do I need to install OracleClient to every user? If so, it will be hectic to do so as its size is around 200 MB and its not possible to ask all the users to install it just for a small application. I have tried adding some OracleClient files like orannzbb11.dll, oraciei11.dll, iraops11w.dll etc. But in vain! Could anyone please suggest me a work-around or a way to accomplish this?

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Make A Data Driven App To Store Dvd Collection

May 12, 2009

I am using VS2008 Pro. I have a simple DVD database built. I'm trying to make a data driven app to store my dvd collection.One of my tables is Actors and is structured as follows.[code]On a form in my app I have a combobox. I'm trying to make it list FirstName LastName ie. Will Smith. I know how to make a query that'll take the LastName and FirstName fields and list it as Actor. I'm having a heck of a time getting it to do that in the combobox as it'll only let me use one field for the display and won't let me use the query I've made.[code]I keep getting some error about schema don't match default query. I know I could simply change the table to only have one field that holds first and last name, but from what I understand that's not proper db practice. I've searched this site and google until I was blue in the face at looking at soulutions that don't match what I'm trying to do.

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Database Driven Mail Merge Application Embedded?

Jun 24, 2010

I am trying to have letter templates (word documents) that are stored in sql server VarBinary(max) to be accessed via a web application where they will be edited and saved back to sql server by directors of our company. Then various managers will be able to select an existing template (word document), make any additions, and mail merge with a list of customers to print or save the letters.

I am looking to open up word within a web page much like you would an email in outlook, edit it with spell check and the like, and then save it back in sql server. I am able to get word to open from a file but it is outside of the web application in a separate word document. I am storing the word document in sql server but am unable to open it in word without having to save it to a disk (why should you have to go to a disk for viewing or editing?). I am able to programmatically mail merge but that is in a separate word application.

I am finding bits and pieces on the web but nothing that will pull things together such as embedding word but in a windows app not a web app. Mail merge from a file not from a database, converting a byte array to word in a directory but not on a web page.

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Create A Very Simple (to Begin With) Database Driven Application?

Nov 27, 2011

I want to create a very simple (to begin with) database driven application. The company I work for have very kindly said they will host any SQL database I create, they have a remote server that we all connect to for files etc.

So I want to be able to create an SQL database that they can host and have my colleagues and I install the application local on our machines.


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Asp.net - Write Use Case(s) & Test Driven Development For Binding A Gridview?

Mar 9, 2011

I'm still trying to understand and use Use Cases and Test Driven Development, but having a hard time crossing the line. I'm hoping someone can provide a good example of how setting a datasource and/or databinding a gridview could be accomplished using Test Driven Development. Here is my pseudo approach at it.


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Database - Design And Deploy A Data Driven Desktop Application?

Jun 28, 2011

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?

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Making OOP Via Observer Paradigm And Easily Adaptable To Test Driven Dev't

Apr 25, 2009

How to implement an observer pattern in VB.NET?

Currently I have a lot of working code in VB6 which the company wants me to migrate to VB.NET. Well, that would normally be straightforward ... yes? Unfortunately, not so in our case.... recently, our company decided that I need to modify it to implement the MVC (Model View Controller) paradigm to make it truly OOP and adaptable to TDD (Test Driven Development).

Currently, my move was to start with a simple one, opening a form and then grabbing a piece of text from a textfile and putting it as the caption of the form... now, that is easy.

The problem lies in trying to implement observer patterns ... in the observer pattern I cannot simply call the usual me.caption = mytextstream.ReadLine from the form_load event instead, I need to use objects that would use an interface to register themselves as observers as the form loads but not necessary having to be residing in the form_load event... in fact ... if there is somehow a way for me to make such a thing happen before the code goes through the form_load event then that would more completely separate the View layer from the controller layer which gets implemented through the use of observers and observer related patterns.

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Regex - Match Words Driven From A Database In A String Input

Jun 27, 2012

I am trying to match words driven from a database in a string input using VB .NET
The syntax I am using is so simple:


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Write A Menu Driven Program To Manage A Membership List?

Nov 30, 2011

Public Class Form1
Class Member
Public Name As String


This is what i have so far and its giving me headaches to fix it someone please help with this code assuming that the names and phone numbers of all members are stored in alphabetical order by last name , then by first name in text file residents.txt

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Best Programming Language For Programming Windows Applications?

Jan 28, 2012

I have recently taken a liking to programming, and have programmed a few games in C#,my friend has asked me to program an application for him to use in his shop. But I have no idea of what language is best suitable?

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Forms :: Database Driven Login Form With Admin Backend (Image Heavy)

Jul 19, 2008

How To on a database driven login form. I'll include the Administration Backend to go along with it soon. Dial-Up users should not use this thread, it is image heavy


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VS 2005 Display In A Datagrid Total Consumption Of Gas (litres) With Kilometers Driven (mileage) Between 2 Dates

Aug 29, 2011

i am doing a small project for my business and i got stuck with this 2 weeks ago and still no progress.I have an access db table "store" that has columns: (filldate,brand,model,plateno,mileage,litres) where i am storing these info each time a car in my company fills gas. For example8/25/2011,Renault,Megane,5487844,3943,20).What i want to do now is to display in a datagrid the total consumption of gas (litres) with the kilometers driven (mileage) between 2 dates.

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Get Templated Starter Database Driven Forms Generated In C# Winforms SQL Server Using Some RAD Tool Or Visual Studio 2010

Aug 11, 2011

I hope I got all that in this question title. Let me explain. We are starting on small desktop app that will snowball into a big app with many forms. The database is SQL Server. It will have classic stored procs/functions performing classic CRUD functions. Given a table or stored proc in SQL Server what is the quickest way to create a form with all the hooks to maintain a table.

For e.g. lets assume I have table like this (most code below is pseudo code)

Table Employee
Name varchar(30)
DOB Datetime
Address varchar(100)

From this as source I want to create my Target which is form with 3 labels and 3 textboxes with add delete modify buttons (or OK button to add if not exists or modify if exists)


The code generation tool or technique that will be used should generate the correct db hooks (create SQL parameters, SqlCommand, execute sql.. basic try catch etc. Is there any open source tool to do this ? Some trick or templated approach via VS 2010 ? Worst case any third party tool ?

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Adds A New Row From A Source Table Called "objTablaOrigen" To A Final Table Called "objTablaDestino"?

Feb 26, 2007

My code Adds a New Row  from a Source Table called "objTablaOrigen" To a final table called "objTablaDestino". This tables are passed ByRef because they come from a DataSet respectively. objRowNuevo is The Row that will be added to "objTablaDestino" The data from "objRow" is well copied to the "objRowNuevo" (that is the new Row with type of objTablaDestino).

'The problem occurs when the instruction Add is executed. ¿What happens?  The new row is added as well, but this generates an Exception with the next message:


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Game Programming :: Programming Such As OOP ?

Oct 30, 2011

I avidly create games in VB.net. Being a hobby programmer I give my games away for free. Since I'm a hobbiest without formal training I do try and educate myself on proper programming principles and follow them when programming such as OOP. There are however some things I have obviously missed being self-taught that perhaps I would know if I were formally educated. Once such issue that has really been my bane is how different classes (from now on referred to as objects) 'know' about each other WITHOUT programming specific interaction.

Okay imagine this, you have a space game and the following objects


Now each one of these objects has a Health, X,Y and Z private members and properties that are all inherited from clsSpaceEntity for argument sake. Now one way of programming collision between them would be to code out the following logic in the main game loop


Now this might seam okay if your talking about the simple example above but some of my games have tens or even HUNDREDS of objects that interact in this basic way. Is there a way in OOP to do the following... for each thing that inherits from clsSpaceEntity check against every other object that inherits this type (except itself) and if they collide then reduce health next? This sort of ability for a type of objects/class or whatever to be 'aware' of another and how they are the same/different and interact would save me tonnes and tonnes and TONNES of coding.

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