Custom Server Controls :: Event Handling For Child Controls
Jul 29, 2010
I have a custom ascx user control on my page that includes a dropdownlist. There is an nSelectedIndexChanged event handler that is connected to this dropdownlist. The first time the user selects a value, the page does a postback and the logic executes correctly. However, if the user then goes to change their selection, the event handler does not get triggered.
I am trying to build a custom composite control, which allows me to add custom content to each child control. It's a similar concept to what you have with a GridView and TemplateColumn. The markup used to place the control on the page would end up being something like this:
[Code]....
I have the code below, which allows me to put that markup on the page without throwing any errors, and it renders all the correct HTML, except it doesn't render the contents of the ColumnTemplate. I have replaced the Render() code with a comment because it's quite long winded and doesn't add anything important here:
[Code]....
I have tried to follow examples on MSDN and other forums but I can't make this work. I think I'm missing the code to render the contents of the template, but I don't know how to hook that up.
I created a customDropdown usercontrol with Events and It worked fine.
Now I stored the path of the ascx file in the database table and i want to Load the ascx file and handle the Events dynamically in an aspx page.
To Load the usercontrol and access the public properties and method, I need to know the object i am trying to load, right?
For Example
FeaturedDDL c = (FeaturedDDL)Page.LoadControl("~/FeaturedDDL.ascx").
But I dont want to hardcode objectType "FeaturedDDL", coz i dont have that stored in my Database field.
Since I am loading the usercontrol by getting the path and name of the usercontrol from the database table,how will I know the ObjectType at that time?
How to accomplish that and also how to handle the events for these type of situation?
I have been trying to implement an extended GridView that eventually will include a panel with a number of filter options outside of the grid iteself.
As a test I have added a dropdownlist and a linkbutton but when these are rendered to the page they are rendered as plain HTML with none of the javascript or ids that are generated for server controls as a consequence the postback event is not fired when a dropdownlist item changes and the linkbutton is rendered as plain text.
I'm creating a custom ASP.Net GridView and I want to be able to alter the __EVENTARGUMENT value but I can't figure out how to capture the returned value on the server side.
I'm creating the ability to have a collapsible representation, so the first level is the standard GridView and I will insert additional rows via JavaScript if they expand the first level row.
My problem is how to create a link on the selecond level rows that posts back with custom data.
I am trying out some code which enables me in creating a page with extension .asp2
The tags included will also be custom, something like:
[code]....
I have done the necessary changes so that ASP.NET identifies the extension. I have also kept a mapping of custom tags and asp.net/html tags with myself. With this I am able to render the page on browser. But how can we do event handling(usually done by page postbacks and code) in such a scenario?
I built a webcontrol showing a complex user interface with a lot of javascript. Basically my webcontrol is similar to : [URL]
Now that most the user interface is working properly, I'm stuck with the following issue: I want to add a button (html button tag) which has to trigger an event. I have been able to declare the event, the event args, the delegate,etc. The page using my control may assign a handler and that handler is called correctly when I explicitely call OnServerControlClick (The name I gave to the event). I cannot make the link between the button in the user interface and the event in the webcontrol source code. When the button is clicked, I get an error message saying a dangerous Request.Form value has been detected.
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 come from the Windows forms side and started using ASP.NET. I have not found how to use event handlers properly.Basically I want to create a shopping cart web control. When a purchase has been made I want to raise an event with products in the purchase. I would like to have the shared/static event and delegate on the web control and then, maybe in Global.asax (if not possible elsewhere) handle that event.
How can I do this? It seems I cannot access objects from other pages/controls.
I have a custom control which contains (amongst other things) an imageButton.
I'm adding a handler to the "click" event of the imageButton however when the button is clicked the handler routine is not called. where I am going wrong with this? should I be handling the click event in some other way?
I have a custom ascx user control on my page that includes a dropdownlist. There is an onSelectedIndexChanged event handler that is connected to this dropdownlist. The first time the user selects a value, the page does a postback and the logic executes correctly. However, if the user then goes to change their selection, the event handler does not get triggered.
In ASP.Net I have a few custom controls I've made. I utilized jQuery where it helped also. Well, one problem I have now(with obvious, but "bad" workarounds) is that for each user control I need to execute some code from within pageLoad($(document).ready will not work with update panels). Well so now my problem. I need to have two custom controls attach to the pageLoad event. What would be the best way of doing this? I can't just do
because these custom controls can be used more than once on a page and the script needs to run for every single instance of the control, plus what if I had 3 different custom controls on the page? the only method I've come up with is something like this which seems super hackish:
Are there any better ways of handling function conflicts like this? I have also seen this MSDN article but what it suggests doing seems worse to me than what I am currently doing.
My CompositeControl creates dinamically several RadioButtonLists according to the DataSource information. These controls are added to the Controls list and rendered in CreateChildControls event.
I need to create a LinkButton that clear a specific RadioButtonList selection and do a postback, to load the DataSource information again (some selections changes the data that need to be loaded from the database). For each RadioButtonList, I've put a LinkButton and assigned the Click Event to a method inside the same CompositeControl, to do the RadioButtonList cleaning.
Unfortunatelly, the LinkButton doesn't trigger the Click Event. In HTML code, the link has the "onclick" attribute setted with the asp.net event, but when clicked, nothing happens.
For test purposes I have created a simple button control that extends CompositeControl. I am able to place it on the page with a <asp:Content... and the Click event Bubbles without problem from the Control.
Now, here is the problem I am facing Due to design requirement I need to read the assembly and the classname from a table and dynamically create the control and add it to the <asp:Content. And when I do that the click event will not fire! Where am I going wrong.
Here is the code in the ButtonControl.cs namespace Reports.Web.ServerControls { [DefaultProperty("Text")] [ToolboxData("<{0}:ButtonControl runat=server></{0}:ButtonControl>")] public class ButtonControl : CompositeControl { protected override void CreateChildControls() { Button btn = new Button();
I have a DetailsView control bound to an ObjectDataSource within a User Control (.ascx). It appears that the DetailsView.OnDataBound event is being fired on every page load or postback.
I do not see this behavior with a similiar DetailsView directly placed on an aspx page.
In one of my ASP.NET webform application I want create dynamic controls and add Event handlers for those dynamic controls..For example when I click a button I want to display a list box and I want to add SelectedIndexChanged event for that list box.I have errors in doing this... Here's the code I tried out... I think there are errors due to my lack of knowledge in postback
[Code]....
[Code]....
DLabel is a existing label control...*** When I click the button I get the ListBox... When I select the Item 1 the page reloads and nothing is displayed in the Label.
I have created radiobutton list dynamically in my app'n...can any one tell me how to handle the selectedindexchanged event for the dynamically created radiobuttonlist. I just want to capture the value of radiobuttonlist and store it in the database.