In my page I have a 'Button' when I click it, it loads an instance of my 'UserControl' to a 'PlaceHolder' .. I've used the 'UpdatePanel' but it was a hazard! .. I think it's because the Asp.Net 'Ajax' sends the whole page to the server and behind the scenes it actually causes a full PostBack. and it will help me if I could implement a partial PostBack so I won't need to save or access my database each time I reload or click the button to re-assign the values to my UserControl.
So I was hopping for some samples implementing a partial PostBack to load only one instance of my UserControl.
I can't post the code in my page here because it's a REAL MESS! .. but if you really need this to help me then maybe I could send this and post a clean solution here on the question.
Thanks for your time .. I hope there's some simple answers to my question because I'm really hopeless here!
The UpdatePanel always causes a postback to the server for the entire page, and only updates the UI's within the update panel. That's just how it will always work. If you only want to load a user control, consider using a JQuery approach to pull the user control from the server and render it via client-side JavaScript.
http://www.codeproject.com/Articles/117475/Load-ASP-Net-User-Control-Dynamically-Using-jQuery
http://samuelmueller.com/2008/12/dynamicloader-plugin-dynamically-loading-asp-net-user-controls-with-jquery/
HTH.
Related
I am forced to use Web Forms in my project, and sadly, Web Forms only allow - If I may - "Strict" Websites to be created.
Whenever you need a Button you need to put it in a form, and then you need another button which has nothing to do with the previous button, and you can't have 2 forms,
And the idea of putting a DIV that fires a server side (C#) method is kind of difficult, okay it may be easy but all I have found are "tricks", not an "official" clean way.
So I have this idea of making a webpage for each action in my websites.
For Example:
Let's say I wanna click on the ARROW that raises the rating of this question, I would put something like this.
HTML
Rate Up
And Some CSS Codes to make it look like a beautiful button...
Okay now this will take me to a page called Rating.aspx with 2 parameters, the first parameter is the ID of the question that I would like to raise its rating, and the second parameter is either UP (+rating) or DOWN(-rating).
On the Page Load method of Rating.aspx, I would update the database, then redirect to the question page.
This will work perfectly, BUT, is it a good approach? is it professional? (put in mind that there will be many actions to preform like that...)
With ASP.NET you better use server controls. Better way of implementing that is using or , that actually renders your anchor tag. But you can attach OnClick event handler to this control (link button) so after clicking there would be automatic POST to server. The same page cycle for the current page will take place (this is called PostBack) and your attached event handler will fire, where you can actually make changes to the database. So you don't even need to create any other pages for tasks like this. Every server control has specific set of events like OnClick for buttons or OnSelectedIndexChanged for dropdown lists. You can even create your own controls or derive from existing ones and create your own events.
Take a look on following links for more information:
Button Click
Event Handling in ASP.NET
ASP.NET Page Life Cycle
I have a search button in a asp.net page that show a pop-up and by closing that some controls are be added to a panel in my form using AjaxManager of Telerik.
I've used the Telerik:AjaxUpdatedControl to say render the panel everytime a search is done.
But my proble is when search is done for second time the controls that had been adde for first time will be removed.
how can I overcome this problem?
Dynamic controls are not created after a postback. You have to recreate them every single time. (Their viewstate is still maintained you just have to create them with the same ID and in the same place within the control hierarchy).
The DynamicControlsPlaceholder control does this all for you. It is available at - http://www.denisbauer.com/ASPNETControls/DynamicControlsPlaceholder.aspx
However I would suggest you use it for as little as possible. Heavy usage of it can cause performance to suffer.
I have a menu on a .aspx page, which will load a specific user control depending on which menu option is clicked. This part is working fine.
The problem I'm running into is when I instantiate a post back from the dynamically loaded user control, the .aspx page is reloaded. Now after researching a few of the other questions on here, I gathered that I have to recreate the User Control each time the post back is instantiated. However, the question I have might be quite simple, but how do I reload the specific User Control (and fire an event such as OnClick) based on what is posted back to the server?
So my question is: What exactly gets passed back to the server on post back, and is there something in the post back request that will allow me to load the specific control? If there is, how would I get to it?
To do it the manual way, you would have to recreate the control(s) before ViewState is reloaded, like during OnInit for example.
There is a control called the DynamicControlsPlaceHolder that takes care of persisting dynamic controls for you. It's a definite time saver, and it makes persisting dynamic content easy.
Here is a link to the control:
http://www.denisbauer.com/ASPNETControls/DynamicControlsPlaceholder.aspx
To better understand what postbacks do, you need to understand the ASP.NET page lifecycle. Here is an MSDN article that explains it in detail:
http://msdn.microsoft.com/en-us/library/ms178472.aspx
I am struggling with finding clear answers to dynamically creating the same page over and over. The questions and samples I have found seem to be all over the board on this topic. I have studied the life cycle and still seem to not have a clear answer as to where code should go.
I have a master page and a content page. All the content in the content area needs to be dynamically created (text boxes, ddl's, page tabs, buttons/onclick etc.).
After a user fills in data and clicks a submit button, I need to read the values off the form and rebuild the page completely again (not add/remove controls to current content).
My question is then.
Where do I put my code to build the page?
Will this area allow me to use IsPostBack so I can rebuild content with Request.Form values?
Will my buttons _Click events work?
Are there any working samples out there you could direct me to?
Thank you very much for the feedback...
I don't know all the answers to your questions, but I hope this may get you started. When dynamically generating the UI through code, this happens in Init. Controls dynamically loaded on Init is key because between init and load, on postback, viewstate is loaded for these controls.
This means you need, on every postback, recreate the page as is to match the previous control tree, then deconstruct it after init and recreate the new UI, if something is supposed to change UI wise. This is because it validates the tree structure to determine its the same UI. Now, if you don't need viewstate, this may not be as much of an issue. I haven't verified this without viewstate to see if it behaves different.
It depends how dynamic you need it, whether you need viewstate (is a big factor).
HTH.
Try creating the controls in the page's PreInit method. "IsPostBack" should work and the click event handlers should work as well.
What you need is a web user control, see ASP.NET User Controls
Brian's advices are good and you should follow them.
This might not really answer your question but still I add it as an advice. I'm professionally creating ASP.net web applications at quite a large scale and from my experience I can say that too much "dynamics" is usually bad and should be avoided because it just introduces complexity. Normally you might want to expose UI parts into ASP.net UserControls or if you want to make them even more reusable (if that's a factor) then into ASP.net Server controls. Then you replace different of them dynamically rather than creating everything from scratch.
Im using ASPxPopUpControll in which I have ASPxCallBack panel. THis CallbackPanel was embeded there because I wanted to have solution based on callbacks despite of reloading page each time.
In this CallBackPanel I've embeded asp:Wizard control.
What I want to achive is get rid of postbacks after clicking next previous etc buttons in this wizzard.
Any hints?
Maybe there is other way to create nice wizard without any postbacks ?
thanks for help
The ASPxCallbackPanel cannot intercept postbacks and "convert" them to callbacks as the MS UpdatePanel does this. So, a possible solution is to replace the ASPxCallbackPanel with the MS UpdatePanel and use the Wizard inside it. One more solution is to use the ASPxPageControl, position all required controls in its Pages and manage them manually.
I would recommend looking into ajax and jquery for asynchronous postbacks, that way you don't get a page refresh and you would only need to update a smaller part of the ui.