Force An Event Handler To Fire For A Custom Control On Every Postback?
Feb 11, 2011
I've created a UserControl that is dynamically placed onto my page during the Init event. It populates and works great, but I'm left scratching my head at how to retrieve data from it during a postback.
It's effectively a multipick combobox that is manipulated entirely using clientside JavaScript (I'm using jQuery heavily). Inside the control container element, I render an empty DIV element that contains all of the selected items. As the user selects items, I generate DIVs within that container DIV that includes some markup. Of interest to me on the server side are the contents of a couple of INPUT fields.
After selecting an item, the rendered HTML looks something like:
[code]....
I may be completely off track and this may actually be impossible (or a stupid idea). The only alternative I can think of is to emit actual ASP.NET controls and hook the built-in event handlers.
I have a control which has an ImageButton which is tied to an OnClick event... Upon clicking this control, a postback is performed and the event handler is not called. AutoEventWireup is set to true, and I've double checked spelling etc.... We haven't touched this control in over a year and it has been working fine until a couple of weeks ago.
We have made changes to controls which load this control... so I'm wondering, what kind of changes could we have made to stop this event handler from being called? There is quite a bit of Javascript going on, so this could be the culprit too...
I am creating a custom control. Let's say I'm reinventing the wheel and creating a custom Button control that derives from the UserControl class(only for example)
Well, it of course has a Click event handler. Now my problem is, when do I call this event handler? I know it happens sometime between the Pages OnLoad and OnLoadComplete, but I'm not quite sure what event I can hookup to so that the Click event is raised at the same time as other control events.
I am trying to create a simple custom control where in there is a image button on the control along with a label.
the problem that i am facing is that the image button appears just fine along with the specified properties. But somehow when i click on the image button it does not generate the click event. the page simply refreshes.
I am populating an asp.net listview control from my page_load event. Unfortunately, due to my projects requirements, I have to use a third party control within my listviews ItemTemplate that needs to have database values written to its attributes before my listview control is bound, if this is not the case my control flags a null reference exception error. From some investigation into the listview control, it seems that the only way to do this is through my listviews ItemDataBound event as my thrid party control will hold different value depending on each row.was wondering if it's at all possible to force my listviews ItemDataBound event to fire before I call mylistview.databind();?
I have a page that is using the Ajax asynch file uploader. What I would like to have happen is after the file is uploaded I would like to have it displayed in a list on the page. I am looking for a way to fire a callback event when the file upload is complete. Is it possible using the asynch fileupload control?
THE LAST METHOD _insertin is NEVER FIred UP. The Update pases correctly ands I will not give the code for the object data source.
My purpose is to include code into on insert code that assign value to a column .
Can you take a look. I'm novice to ASP.net .I'm A DBA and would like to Use ASP for UI to May database. I dont have the goal to become profesional in that field.
On my page: a Button1, a ListView1, a Panel1 and inside Panel1 an ImageButton1In the ListView1_PreRender-Event the property Panel1.Visible = false or Panel1.Visible = true is set.1. After first loading of the Page Panel.Visible = false ist set in ListView1_PreRender.2. After the postback click on Button1 the criteria for the visibility of Panel1 are evaluated, thus setting in the ListView_PreRender Panel.Visible = true.
I'm trying to manually create a button and add a Click event handler for it in code. However when the button is clicked the event handler doesn't seem to react on event (or event isn't called).
we tested the code in Visual Studio 2008 and everything worked just as it should. And I'm using Visual Web Developer 2005 XE. So I assume that I'm missing something to be done manually being in VWD 2005 XE, or the problem is in VWD 2005 XE it self.
I am building a web site with visual web developer 2010
I have a class (autoButton) that adds a button to a panel (on Default.aspx) and a handler w/i the same class (classifyEventHandler)
The button appears fine, but when clicked the even doesnt fire, what am I doing wrong?
I tried locating the event handler in default.aspx, but it was not found :P
Imports Microsoft.VisualBasic Public Class autoButton Public Sub makeClassifyButton(ByVal theCell As Object) Dim myButton As New Button myButton.Text = "classify" myButton.ID = "b_classify_" + theCell.ID AddHandler myButton.Click, AddressOf classifyEventHandler theCell.Controls.Add(myButton) End Sub Private Sub classifyEventHandler(ByVal sender As Object, ByVal e As EventArgs) MsgBox("done?!") End Sub End Class
I have a base server control class for all my user controls. Inside this class I have the following declaration:
[Code]....
Concrete user controls used in the application are used always inside a ModalPopupExtender object and the popup it is always handled with server-side code. This means that there are no controls binded to the OkControlID and CancelControlID properties of the ModalPopupExtender.
The responsibility to show the Modal Popup is then given to the aspx that has code like this in the ASPX file...
[Code]....
To hide the modal Popup the aspx just implement the event handler
[Code]....
Last, the event firing is responsibility of the concrete UserControl class that can use any way to do it's work and then fire teh event. This is done through this code:
[Code]....
The problem I am facing to is that in the OnItemSaved of the super class the ItemSaved EventHandler is always null and so the event it's never fired on the aspx page. Where am I doing wrong?
I have a custom class (ServerSideValidator.vb) that validates user input on server side (it doesn't use any of the .NET built in validators, therefore Page.Validate() is not an option for me). I am calling the Validate() method on page.IsPostback event and the class performs without any problem
My issue is, when validation fails (returns false), I want to stop the postback event handler from firing, but load the page along with all the controls and user-input values in them. If I do, Response.End(), the page comes up blank. I can programmatically instruct the page to go to the previous page (original form before postback), but it loses all user-inputs.
I thought of creating a global boolean variable in the page code behind file and check the value before performing any postback method, but this approach takes away from my plan to provide all functionalities inside the class itself. The page object is being referenced to ServerSideValidator.
Seems like all the postback related properties/variables I come across inside Page class are 'Readonly' and I can't assign value(s) to control/prevent postback event from firing.
I have a asp.net page with a button, the event the button needs to perform on it's click event needs to vary, dependant on what options are selected further up the page. The button itself is included in the master page, and it's actions are affected by selections made in the child page.
To do this, I have a method in the master page, that is called by the child page, when a users presses a button, that passes the Eventhandler to be used by that button, that is then assigned to masterpage eventhandler for that button:
public void assignEvent( EventHandler saveEvent) { this.SaveButtonEvent+= saveEvent }
Then, when the save button on the master page, it calls that eventhandler
The event handler is assigned ok in the first section of code, however because pressing the save button causes a postback, the SaveButtonEvent event handler is set back to being null, and so nothing happens.
How can I preserve the contents of SaveButtonEvent Event Handler during postback, or is there a better way to be doing this?
EDIT:
I can get this to work by saving the EventHandler to the session, but this doesn't seem like a great idea.
I understand I need to load my dynmaic control on every postback and preferrably in Page_Init(). But my dyanmic controls are loaded from a dropdownlist selectedindexchanged event handler. Now after any postback, my dynamic controls are gone. How would I force it to load on every postback ?
Can I fire a custom event in asp.net according to my needs ?
I am making a simple chat application for my website.
I am using cache variable to store my chat. When I submit my textbox cache variable updates and text is cache variable is displayed to both the users. Since , I get a postback , my page refreshes and I get an updated value of cache variable but the other user needs to refresh the page.
So, is there any method, which can check if cache variable has been updated and fire an event , so that , I can deliberately force the browser to refresh.
One more problem , I am want to list the online users of my website. ( I need to list all sessions currently active ).
I think , best possible way is to insert current date, time on database after every 10 seconds by all users. How can I get an event which can update a column of database every 10 seconds ?
In the UserControl I am adding dynamic ImageButtons depending on the condition When the page loads and I click on Edit button I have no problems and btnEdit_Click is fired. But after that (btnEdit id removed and btnSave is added) when I click on btnSave the btnSave_Click event does not fire. What could be the problem?
I am new to MVC. I created an application in which I am able to do login. I have used the basic template provided by MS. Now, I have to use registration template. But I need more fields than they have provided in their basic template. I am trying to add my fields manually on register.aspx, but its throwing an error. I tried to add a new content page in shared folder under view, but dont know how the event of register button will handle in controller.
I need a Slider that will only postback when the slider has been moved. Can this be achieved with SliderExtender?
I have a TextBox with autopostback=true, within an updatepanel within a usercontrol. The TextBox is extended by SliderExtender (default settings).
The TextBox's TextChanged event fires perfectly when the slider is moved (MouseUp - standard extender setting). The aspx page is partially posted back, and all is well.
However, if another usercontrol on the same aspx page causes a partial postback, the SliderExtender causes the TextChanged event to be raised - for no aparent reason. This is causing problems.
Is it possible to prevent postback unless the slider has actually been moved?!
I have a small website where I want to display a confirmation dialog after clicking on a button.
When you click the confirmButton the dialog appears. Then you can choose between Yes or No to either continue with the PostBack or to return.
Problem: The first time you get into the site all works fine. But after you click Yes to continue with the PostBack, no click event will be triggered anymore.
I'm learning asp.net page life cycle. I find an article on MSDN [URL] It says that If the request is a postback, control event handlers are called. After that, the Validate method of all validator controls is called, which sets the IsValid property of individual validator controls and of the page. And the picture in the article also says validate fires after event handling. If this is true how can I get status of validator when I handling the event?
I have problem with user control: MyCollection : UserControl
MyCollection contains:
[code]....
Works fine unless I register event for some button:
button1.Click += ...
When click on button, nothing happens - page does postback, refresh but event handler method is not executed. Generated HTML is bit strange. Every page control has correctly generated ClientID including parent container ID.
Button in this collection MyCollection has odd ClientID - itemsAddresses$button1
