.net user control and page binding - asp.net

I have a block of code that contains an updatepanel and gridview that I use repeatedly in 5 different .aspx files. Instead of trying to maintain all 5. I was hoping to create a user control that I could just include in each page.
After starting to write it, I realized that it might not work. The issue is, I will need to bind database data to the updatepanel and gridview inside the usercontrol using Eval. But I don't think this is possible since the code will now be in a .ascx file.
So I was wondering if there is anyway to solve this.
Thanks!

Related

.aspx works but .ascx does not... why and how to fix?

I want to put a ASTreeView web control in a custom web control, ASTreeView sample code is like:
<ct:ASTreeView ID="astvMyTree"
runat="server"
...
LoadNodesProvider="~/ASTreeViewDemo5.aspx"
.../>
LoadNodesProvider is the page ajax called when loading a node...however if I changed the provider to my .ascx file, it does not work:
LoadNodesProvider="~/ASTreeViewDemo5.ascx"
it did not even go through the Page_Load part of the .ascx file
Though this might be related with astreeview itself, I'm wondering what the problem could be? anything I can do to fix it?
Thanks!
It is because ascx must have a container ie Page. You can't use it same way as Page.
ASPX is a page and ASCX is a usercontrol. You cannot ajax call a control, so you probably want it to be a page with the control on it.
While it isnt entirely clear to me what LoadNodesProvider is supposed to do, if you want to encapsulate some code or run a process via AJAX you have a couple of options. One would be to create a web service (you could use WCF for this) that the AJAX method could call. Another option would be to create an http handler (ASHX extension typically denotes this). Using an ASPX or ASCX for this doesn't make a whole lot of sense to me. Proco and Tomas are correct regarding the ASCX file, these are Usercontrols and are not stand-alone objects.
If you really, really want to use an ASPX page/ASCX control, then I suppose it would be best to create a blank ASPX page that has one placeholder, and then attach your user control (based on query string parameters or something I guess) to the placeholder to render out the content for your AJAX control

FormView or not?

I have an ASP.NET page with a Wizard control containing several pages of form fields. The data is collected and inserted to a database from the code behind page. I need to set this form up so you can not only insert, but edit a record as well. Since the form is long and complex, I would rather use the existing one and not make a duplicate one for editing, especially since I want to keep both forms exactly the same and any edits would have to be made to both. But it looks like this is what I need to do if I'm going to databind it. But this would also involve putting the Wizard inside of a FormView, and then I'd have to use FindControl to access any of the fields which would mean altering all my already-existing code (which of course would be time-consuming). So should I manually enter all the values from the code behind instead of databinding it? Which is better, to use a FormView and have duplicate forms (plus have to go in and redo the way I access the fields), or to do everything from the code behind?
I cheat in this circumstance. :)
Create each screen as 2 separate user controls
One for edit, and one for view
Then you get access to all you usual coding
Then embed the controls into the Wizard/FormView
I would suggest you to Go Ahead using FormView, as using DataBind control you have more control the functionality and layout Insert/Edit/View template. Since you have specified that your form is very complex and long, if you control from code behind you have to do lot of work to handle this in code behind and lot code required.
Since I have personal experience to develope very complex form using FormView and it was easy for me bind the Value in directly in formview instead if you assign/Get Values of each conrol in code behind and sometimes you have to hide.

Dynamically creating many instances of ASP.NET usercontrols: How do I create it, and where will my conflicts be?

I haven't seen this implemented before in ASP.NET, but am thinking about a UI that would look and act like this:
Conceptual Overview
A TabControl is loaded and the first tab contains a grid
When a row is double-clicked, a new tab is created with the record detail
The content of the tab/record detail is created by a usercontrol
Many tabs could be created, and therefore many instances of the usercontrol will be created
I know ASP.NET will rename my (runat="server") ID's for me, and that I can use jQuery or ASP.NET server-side code to work with the ID's... My concerns are:
How can I ask ASP.NET to generate a unique ID for each Nth instance of my usercontrol (to be rendered in a placeholder)
How do I actually create that extra instance of the control?
What else do I need to keep in mind?
Since I don't want postbacks I'm considering basing my implementation off of ComponentArt's Callback Control, and using ASP.net usercontrols to achieve this effect. This will allow me to do most things that require a postback, but won't refresh all the elements on a page... just the section that contains the user control. That being said, I'm not tied to a particular implementation.
You should look into the Page.LoadControl method. It works nicely and as far as I remember you put placeholders on your page and load the controls into the PlaceHolders, that's how you control the ids.
One thing that doesn't work out so well with this approach is when your control raises events that your Page object has to handle. If your control is selfcontained however you shouldn't have a problem.
This might help you get started:
http://www.codeproject.com/KB/aspnet/LoadingUSerControl.aspx

asp.net 2.0: update formview with jquery

I'm struggling with an issue I just can find a solution for.
First of all, I can't use asp.net AJAX or anything else thant standard asp.net 2.0 as the server admin won't install anything else.
So here is, what I try to do. (For the curious, skip to the bold question below)
My page consists of several parts, each of which gets loaded by jquery.load(url). One of these page parts gets filled with an aspx that contains a form view. As I don't want to have postbacks, I switch to the EditTemplate of the form view by a simple click on a regular html button that submits a parameter indicating the aspx page to switch to edit mode, e.g.
Page_Load(...)
{
if(Request.Params["SwitchEditMode"]) SwitchEditMode();
}
This works perfectly! Now here the part where I'm stuck. The elements in the EditTemplate are based on a select from a database view and bound to the fields by <%# Bind("xx"). Then I have a html button (no asp control) that submits a parameter to the aspx page that tells it to invoke the DataSource update method. In the dataSource_updating method I look for the controls that contain the values I want to save. But these values are always the same, as when I switch to the edit view. No changes I make in the textboxes or dropdowns are preserved.
A long story short, the question how to save the values from EditTemplate back to the database with jquery?
Up to now I tried several approches, that didn't work out.
In the updating() method look for the controls by FindControl and set e.Command.Parameter["xyz"] = foundcontrol.SelectedValue;. The values are always the same as in the beginning.
Set <asp:parameter name="SampleValue" /> and in the EditTemplate <asp:TextBox Value='<%# Bind("SampleValue")#> The values are always null.
Set a hidden input field with the selected value via javascript. This doesn't work as the control within EditTemplate are only visible after the switch into edit mode
So maybe I'm totally wrong with my ideas, heading into a totally wrong direction and this can be accomplished much easier, but up to now I don't know how to achieve this. I could do it without ajax, but for the user experience I'd prefer the version with jquery.
For all that have read this far and not got confused :-), thanks for your effort!
Best regards,
Andreas
I would forget using a form view and just use a regular html form with regular input controls. Return an object from your web service that has all of your values and populate the controls with ajax and then subjmit with ajax. Either do fully asp.net or fully html/jquery with asmx back end. Otherwise it's just too confusing.
If you load both "modes" of the FormView into the same page using AJAX, you're probably getting duplicate field names. One of them contains the unchanged values which are being saved. How will ASP.NET know the difference? You only want to submit the ones from the EditTemplate, which will require a separate form (or some other hack).
Or perhaps your HTML submit button isn't giving ASP.NET what it needs to repopulate the controls. Are you using ViewState in the page with the FormView?
All in all, this sounds like a hairy combination of technologies... as you well know.

ASP.NET: Bind Repeater using jQuery?

I have a Repeater control that I bind server-side. It repeats a series of divs, and does so with no problem. I have some buttons that I use to sort the repeater (newest, highest ranked, random) and this works the way it should.
I would like to improve my user experience by making the buttons sort the divs using Ajax/jQuery somehow so that there is no page postback and the user does not lose his/her spot on the page.
Is there a way to use jQuery to access server-side code like this, or use Ajax to re-bind a server-side control?
Thanks... if I need to list more details, please let me know!
EDIT I'm aware of UpdatePanels, but I would prefer not to use them if I don't have to.
Have you considered moving the Repeater's functionality to the client-side?
Doing it that way, functionality like paging and sorting is not very difficult to add. In fact, you can lean on the framework pretty heavily by using ADO.NET data services as the service layer.
It's relatively easy.
Move your repeater to a separate custom control, let's say MyControl. Now repeater in your page becomes uc1:MyControl.
Wrap MyControl into a div:
<div id="mydiv">
<uc1:MyControl ID="MyControl1" runat="server" />
</div>
Create a new page, pgMyControl.aspx, that contains MyControl only.
On your main page, add jQuery handlers to your sort links. Use load method to dynamically replace div contents:
$('#link_sort_random').click(function()
{
$("#mydiv").load("pgMyControl.aspx&sort=random");
}
Use QueryStringParameter in datasource inside MyControl to change order. Or use Request.QueryString in code-behind file.
Using an updatePanel or a jquery Ajax postback are the same thing essentially. Both will ask your code to fetch the new query, then make your control render itself, and then feed the HTML back to the client as a partial page render, and then insert the content in place of the old content in the same DOM location.
It is considerably harder to make JQuery and ASP.NET talk to each other this way due to the nature of web controls and their lifecycle that determines when they render. An updatePanel knows how to call all this, maintain proper viewstate and return the result to the correct location.
In this case, don't make things any harder on yourself, use the updatePanel unless you have some very specific reason not to.
EDIT: If you're having JQuery issues with update panels it is probably due to the fact that new DOM nodes being created. JQuery has the live event to handle this. It will notice when new DOM elements are created and match them against your selector even after the document ready.
Maybe it's an OT, but you can consider to change the way you bind even the client and the server control, using XSLT transformation instead od the classics server controls.
You can find an example here (sorry, it's in italian...).

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