Everyting is OK, but when I click on F5, it refresh the page and run the code another time. This means a new record is added to the data base on each F5.This is my code, do you have any advices?
Imports System.Data.OleDb
Partial Class Default2
Inherits System.Web.UI.Page
[code]....
I am teaching myself VB, and when I try to run this program, I am getting "An error occurred creating the form. See Exception.InnerException for details. The error is: Object reference not set to an instance of an object." If I was to declare the variables inside each event handler, the program runs, but why won't it run when I make the scope public? Seems repititous having to declare the variables in every event handler. [code]
View 7 RepliesFor several days now I've been messing around with Ajax calls using different combinations of javascript, ASP controls, and regular controls. I've gotten a bit of understanding about what's going on, but using ASP controls still hides too much of the machinery, and I want to have a deeper understanding. With that aim, can anyone tell me why the following setup doesn't quite work?I have a file "Testy.aspx" with the following:[code].....
So, I hoped to make my .aspx file do double-duty both as the regular-page request handler as well as the Ajax request handler. However, when I click the button ("baroo") to generate the Ajax request, the result that ends up written back to the "testytext" div is the raw html for the entire page, as if under normal request conditions. Clearly, my attempt to override the page request by making the code-behind implement IHttpHandler and supplying an "Overrides Sub ProcessRequest" method is not working. The server is still treating the Ajax request as a normal request, and in fact my own "ProcessRequest" method is never even called.Is it possible to build a page/handler like this? How can I intercept the incoming request from the client and respond accordingly?This is how Ajax works, right? So it must be possible.Again, I'm deliberately doing this as an excercise to avoid the use of "magic" ASP controls like UpdatePanels,
My current problem, as stated in the title, is that I am trying to create a series of buttons from a custom class within app_code and place them on a master page. The whole reason for this is I do not want to have to copy and paste event handlers on the content pages.
However, upon the click of these buttons I need for a method on the content page to be called and update html within a div of the content page.Is there any way to accomplish updating the div of the content page from an event handler in the custom class? Remember, the method that updates the div exists on the content page.
I am trying to learn Visual Basic and am working through a text book that my son used for a class. Each time I create an event handler by double clicking on the design page, the code that automatically populates is almost identical to the code in the book, except the byval portion is omitted from the code.[code]
View 2 RepliesI have a windows application that has a tab control with 5 different tabs. Each of these tabs has a datagrid view that is populated with data on form load with data from SQL Server. I have an event handler for the datagrids for CellValueChanged that appends an asterisk, "*" to the tab, when a change is made, this is meant to mimic the same behavior in VS or SSMS. The issue that I have just realized is that on page load as the datagrids are populated this event handler is raised thousand of times. I have included an If Then statement to exit the sub if it occurs during page load, but am concerned about the performance implications, if any. Is there a better way to handle such functionality? Possibly a way to ignore the event handler on form load? If not is there a negative impact leaving this functionality in?
View 7 RepliesThe 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
[code]....
How do I get a Event Handler to fire from within a nother Event Handler?
View 6 RepliesI have a gridview control on my asp.net page(vb.net). I also have a "cancel" button, that when pressed, is supposed to clear the gridview of it's current contents.
However whenever the cancel button is pressed, it just reloads the page and the gridview is still there with the same data that I wanted clear.[code]...
I have a listbox, a textbox, and a button. The button populates the textbox with the selected item & value of the listbox. As below:
Protected Sub GetVariables_Click(ByVal sender As Object, ByVal e As EventArgs) Handles GetVariables.Click
Me.txtLetter.Text = lstNames.SelectedItem.ToString & lstNames.SelectedValue.ToString
End Sub
The problem I have, is that when doing this it reloads the page each time. Any way around this?
remove an event handler from within the event handler?
I have a class that gets data from a hand scanner. When the scan is complete and the data is validated, the class fires a custom "ScanComplete" event and returns the data in a custom EventArgs.
In the calling program, I'm creating an instance of the scanning class and adding a handler for the "ScanComplete" event. In the event handler I get the data that was scanned and then remove the handler.
It seems to be working but it feels wrong to remove the handler while I'm running inside the handler. Will this cause a problem?
I'm trying to complete this airline reservation application, but having a problem in this part of the question:Creat an event handler for the FlightBindingSource's PositionChanged event: select FlightBindingSource in the class Name combobox then select position changed in method name combobox to creat the FlightBindingSource's PositionChanged event handler. Write a code to access the currently displayed flight object and pass its flightNumber to method DisplayPassengers as a decimal.This Is my code so far:
HTML
Public Class AirlineReservationForm
Private database As New ReservationsDataClassesDataContext()
Private Sub FillAll()[code].....
Below I create an array of labels. I would like to add an click event to my labels. Can someone point me in a direction?
[Code]...
HOW TO RUN THE JAVASCRIPT FUNCTION ON PAGE ONLOAD EVENT IN CONTENT PAGE OF MASTER PAGE.? means i have masterpage and the content page of master page namely default.aspx in vb.net.i wanna run javascript function in Default.aspx and i have called the function body onload in master page.when i run my website it shows the error "" Microsoft JScript Runtime Error : Object Expected ""
View 4 RepliesWhen I utilize AddHandler in VB to add my own method to the Click event :
AddHandler Button.Click, AddressOf myButton_Click
I see that my code executes last - after other event handlers for the Button_Click event. Is there a way to insert my event handler in front of other events so that it executes first?
I want to get domain name not for remote ip. i have two domain(website). example [URL] and [URL] in a2 domain send a request to a1 domain's page like GetRequest.ashx the example of http request is
[Code]....
I am creating aplication that displays images in many different ways using Picture Boxes. Single page with tabs, double page using fading in/out effect, double page 'page flip' effect and single page auto scroll effect which I have problem with. I am dinamicaly creating picture boxes, loading images, placing 'path' to a file in tag and adding handler to each picture box. All fine...
[Code]...
I'm working on a simple image tagging and searching app. I've got my images uploading to the DB, the tags being applied, but am failing when I pull them back - the images don't render. I found this here on SO, but I'm not able to get it working.
[Code]...
I have created a WebBrowser and I want to catch the page that says "This program cannot display the webpage " instead of loading that page I want to display my own html code for that error. And also to catch error when loading an html page from a disk which is not present at all. (file not found)
View 7 RepliesI have a VB 2008 console application .NET 3.5 who handles large data tables in a SQL 2005/8 database. Sometimes when SQL server do not response as application expect. Then SQL Connection change status from open. I try to get the event of changed connection string before error occurs.
1 - SQL Connection status changes from open to another status
2 - When this event fires a fix sub routine or function starts and fix the sql connection
3 - Return back where SQL Connection was when status was affected by program.
My app is a large list of SQL Commands who runs in a class orginsed as a simple list of sqlcommands.When a SQL Connection fails I will start at the last point in the program after SQL Connection are open again.
i am wanting to add handler for controls i add at Page_load at page load i added several image buttons and applied the image urls using -i used the borderwidth propertiy for padding as was having trouble getting a cssclass to work. [code] what i want these Image button to do is when clicked a larger image in another panel will appear so i will need to assign the clicked buttons image url to the large image controls, image url
View 2 RepliesIs it possible to determine using VB.NET whether a certain event has any handlers attached to it? I don't own the event, in this particular case I want to know which of the items in a Windows.Forms.MenuStrip have their ToolstripMenuItem.Click event handled.
View 1 RepliesI've been looking for a solution to this for several hours now and cannot find a solution.
The Scenario:I have a masterpage baseclass (called basemaster)All of my master pages inherit from basemaster
basemaster defines an event 'Public Event HandleClickEvent As EventHandler'I have a masterpage named master1
master1 defines an event handler 'Public Shadows Event HandleClickEvent As EventHandler'master1 has a user control named usr1 usr1 has a button that raises event ButtonClicked when clicked I have a page (thePage) that uses master1 thePage has a button click event handler that it registers like so: 'AddHandler Master.HandleClickEvent, AddressOf HandleTheClick' master1 has code something like:
Protected Sub Usr1_ButtonClicked(ByVal sender As Object, ByVal e As System.EventArgs) Handles Usr1.ButtonClicked RaiseEvent HandleClickEvent(sender, e) End Sub when thePage loads I see it register the handler on master1 when the button is clicked, Usr1_ButtonClicked is fired and I step through the RaiseEvent but HandleClickEvent on thePage is never reached.
This code is part of AjaxControlToolkitSampleSite. To be exact, it is in the AsyncFileUpload control[code]...
View 4 Replieshow to add one event handler name clearallboxes that handles the TextChanged event for both examples(Customer text box and Total text box ) This event handler should clear the values in the text boxes that display the results.
View 4 Repliesi have a page which dynanically create a link when it load, after i click on the link it should loop in the database fetch all the record and display another set of link , then when i click on these link it should give me all information about this particular record it like this one
Q: when the page loads, it creates the first link which is associated with an event handler, it fire the first event handler (Getname) but it not firing the second event handler (GetnameDetails)
Protected Sub Page_Init(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Init
If ViewState.Item("nameload") IsNot Nothing Then
If ViewState.Item("nameload").ToString = "True" Then
[Code]....
I have a form that is derived from a base class. When the form is created a behavior class is also generated that handles event management, bindings, etc...I create a form instance(FormFoo). When the associated behavior class is created it has a method in it with a signature of: grid_EventA(....) Handles grid.eventA
I want to handle EventA in FormFoo instead of the behavior class so I remove the handler that was generated in the behavior class and add a handler that points to a method in FormFoo. This all works just peachy. The event is properly handled in FormFoo only.
Next I instantiate a modal form(FormBar) via a button click in FormFoo. I then close FormBar. Now we have a problem.When eventA fires it is now handled from the Event handler in FormFoo AND in the behavior class associated with form foo(bad).Is the event handler in the behavior class(grid_EventA(....) Handles grid.eventA) getting resubscribed when the form gets focus again? I don't understand how that event is getting resubscribed.
I figured it out I removed the Handles grid.EventA from the method signature:
grid_EventA(....) Handles grid.eventA
Then I added the handler during initialization of the BehaviorClass using:
AddHandler grid.EventA, AddressOf grid_EventA
Once I did that the problem went away. It appears that when you use MethodName(..) Handles that the event bindings get reset when the control comes back into focus.
In C# I can test for this...
public event EventHandler Trigger;
protected void OnTrigger(EventArgs e)
{
[Code]....
Is there a way to do this in VB.NET? Test for null I mean?
MORE INFO
I forgot to mention. I have classes written in C# but I am writing my unit tests in VB.NET.
I am trying this in the unit test...
If myObject.Trigger IsNot Nothing Then
''#do something
End If
This is causing a compile time error which says ... "Public Event Trigger is an Event and cannot be called directly. Use the RaiseEvent statement to raise an event."
I am trying to convert this code written in C# to VB:[code]This is what I have currently, but it always throws an error when I run it:[code]
View 3 RepliesAt the beginning of a VB .NET function I remove an event handler and add it again at the end of the function because the function's code would trigger those events and I do not want them to trigger for the duration of the function. This usually works, but I have run into a few situations where the event still gets called even though I have already removed it. Sometimes removing it twice at the beginning of the function fixes it, but other times no matter how many times I remove it, it still fires.
Edit:The code is in a Form that has a virtual mode datagridview. I want to run some operations that will trigger the CellValueNeeded event for the datagridview without that event being fired (because it will interfere).
Public Sub DoEventRaisingStuff()
RemoveHandler grid.CellValueNeeded, AddressOf grid_CellValueNeeded
'Do things that would trigger CellValueNeeded
AddHandler grid.CellValueNeeded, AddressOf grid_CellValueNeeded
End Sub
Removing the handler multiple times does not prevent the event from firing, so it doesn't seem to be added multiple times somewhere else by accident.Is there a way to find out what event handlers are active?