I'm using a file manager-type WebControl that does lots of postbacks. It's placed inside a Page that is relatively complex. I would like to prevent the WebControl from causing the whole Page to go through the lifecycle. An UpdatePanel helps a little, but not enough.
Is there any way to isolate the WebControl from the rest of the Page? The only way I can think of is sticking the WebControl in a separate Page and creating an iframe in the original Page. Unfortunately that also means my WebControl properties/settings are no longer in the original Page. If I want two instances of the WebControl with different settings, then I have to create a Page for each setting and reference the correct one in my iframes. Not quite as "drag & drop" as I would like. Any other suggestions?
Hard to tell, you can't prevent a control from going through lifecycle; is there anyway to identify though, that during a certain page postback, you prevent the code from running in each event handler by doing something like:
if (_shouldNotRun == true)
return;
//Event handler code
Essentially, figuring out some way to indicate whether the control should run may be an option. IFrame would work, but yes you have to deal with the issues you mentioned. Can you give more detals to the problem?
HTH.
Not 100% sure what events possible to override that are called on PostBack. A good source for the Life Cycle of a page (http://msdn.microsoft.com/en-us/library/ms178472.aspx)
But it sounds as it would be better to remake your control to create Ajax webservice requests for the functions that are possible to prevent most of the postback's?
Cheers,
Stefan
Related
I'm writing an asp.net web app. and i've hit a bit of a brick wall.
basically i have 2 pages, the main page with a text box in and a popup that contains a treeview.
My problem is this. when i select a treeview item i want the program to perform some database transactions using asp.net and then pass the value retrieved from the database into a javascript function that passes the data back from the popup page to the parent page. My problem is that i cannot find any way of calling a javascript function from asp.net. I've tried assigning attributes to controls on page load, but this does not work as when the page loads the data has not been retrieved from the database.
Have a look at the ClientScriptManager class. You can register scripts from code-behind that will run when the HTML page loads. Those scripts can call other javascript functions on the page.
There are many tutorials and examples on the Web. Here's one I found that may help but there are many more.
How to use the client script manager
You hit the nail on the head when you said "I've tried assigning attributes to controls on page load, but this does not work as when the page loads the data has not been retrieved from the database." You just need to discover when you're pulling the data from the database, and then assign the values after that. Without looking at your code, there's no way to know for sure, but Page_PreRender is probably a good bet to assign your values...it's probably after you're pulling information from the db...it's pretty much the last place that you can make things happen before the html is generated for the client.
You can invoke a function resided in the Main Page and call that function in the Main Page from the Child Page which is your pop up window.
Please refer to these links for references
http://chiragrdarji.wordpress.com/2007/03/10/call-parent-windows-javascript-function-from-child-window-or-passing-data-from-child-window-to-parent-window-in-javascript/
http://www.webmasterworld.com/forum91/2957.htm
http://hspinfo.wordpress.com/2008/01/12/call-parent-windows-javascript-function-from-child-window/
This one helps with retrieving popups from values using javascript
http://www.eggheadcafe.com/articles/20060117.asp
This one shows how to fire a postback using javascript, and manage it in the codebehind.
http://weblogs.asp.net/mnolton/archive/2003/06/04/8260.aspx
If you put them together, and use Control.ClientID to find the actual "html name" of your asp.net controls, you'll be able to set that up in no time.
Might not be the prettiest way to do it in town, and incidentally make little baby Jesus cry, but anyway, it works.
[edit]Oh. I just saw that it seems I answered the question the other way around, or "how to trigger codebehind from Javascript". I think the method I suggest may help you, if you use it right.
The javascript of the popup should pass the information to the parent window, and the parent window function should call a postback when it receives the information.
The javascript of the popup window should be only registered on a postback with the correct information retrieved, so that when the postback occurs on the popup because of the selection of the right information, the window closes and passes the information to the parent page.
The parent page, triggering postback, does the thingies you need it to, and the app resumes "normally" from there on, doing whatever you need it to, outside of the popup page.
I have a very big problem. I am making a CRM (Costumer Relationship Management) System in ASP.NET 3.5
I have based my entire project on DevExpress.com controls and the use of UpdatePanels.
Now one of my pages, which is a central page in the whole system, contains a very big amount of possibilities and therefore a big amount of UserControls.
Now my problem is that it's getting really really slow because of the fact that UpdatePanels are reposting the entire page and not only the update panel. We are talking sometime 3-4 seconds before a popup window appears :(
Is there any way I can refactor this entire system away from UpdatePanels without breaking my neck?
Are there anyway I can optimize my use of UpdatePanels?
The ViewState is also absolutely giant.
Any good ideas are welcome...
There's no way to get around posting the entire page using UpdatePanels. In lieu of redesigning the app here are a couple things I'd try:
Disable viewstate for any controls that don't need it
Set the UpdateMode="Conditional" for your user controls. This won't get around posting the entire page but it will cut down on rendering time a little. Only the content for the specific UpdatePanel will be updated in the browser.
Make sure your user controls have short IDs. The way ASP.NET webforms names controls in the html these IDs get repeated quite a bit if you have a lot of server controls. Same goes for naming master page placeholders. I once cut a large page to half the size by renaming user controls and placeholders.
Since you're a DevExpress user, you might consider taking a little time to learn their CallbackPanel which will allow you to do asynchronous processing without the overhead of the UpdatePanel.
Alternatively (someone please correct me if I'm wrong) but if all of the postbacks are asynchronous (i.e. in an UpdatePanel), wouldn't it be theoretically possible to disable ViewState for the entire page (in the Page directive) without negative consequences? You'd have to test it completely off course, but it's worth a shot.
You'll have to replace some of the postbacks contained in your update panels with real AJAX calls, i.e. send only the data that is required for the action to the server and get back only what's required to update the view, getting rid of the postback and the UpdatePanels.
(You'll notice my use of the terms 'action' and 'view' - yes, I am an MVC fan. The situation you are in is typical of the mess that is easily got into using WebForms and the ASP.NET AJAX controls.)
I must be missing something. Why is your updatepanel is reloading the entire page. The point of an updatepanel is to refresh only what is in that panel, isn't it? Thanks for the explanation. I guess we're talking about reposting the page and not redrawing the panel as I thought.
Try turning off ViewState, especially for grids.
What kind of control is most common on your page? Try replacing those with your own lightweight UserControl or Server Control that does not use ViewState or ControlState
For all Interested I want to add a solution on how to get rid of the Viewstate data on clientside. It does give the server an extra load but if you are in the same situation as me and have a lot of server power and need to take the load of the clientside this is nice.
Let all your pages Derive from BasePage.cs looking like this
public class BasePage : System.Web.UI.Page
{
protected override void SavePageStateToPersistenceMedium(object viewState)
{
string vsKey = String.Format("VIEWSTATE_{0}_{1}_{2}", base.Session.SessionID, Request.RawUrl, DateTime.Now);
Session.Add(vsKey, viewState);
ClientScript.RegisterHiddenField("__VIEWSTATE_KEY", vsKey);
}
protected override object LoadPageStateFromPersistenceMedium()
{
string vsKey = Request.Form["__VIEWSTATE_KEY"];
return Session[vsKey];
}
}
Now you have a key to the viewstate data session instead of the viewstate in your code...
Works like a charm for me on a website with 1000-1200 daily visitors as well.
I have an ASP.NET user control that I'm embedding in another user control. This works fine.
I need to know the best logic/method for detecting when the control is loaded. In other words, I have some display initialization logic that needs to run when the control is initially displayed. Surely there is a pattern for this.
The typical method is to put (!IsPostBack) logic in the Page_Load method of the control. This works great until you end up with a state when the Parent page has already posted back many times. My user control gets added to the page but its display does not intialize properly.
I'm hoping to find a way that keeps this logic inside the control, versus various hacking around in the codebehind of the parent page.
See the following MS article. They have an example that places several controls within a user control and initializes them.
There is another post here on StackOverflow that seems similar. You may want to check it out, and see if it points you in the right direction.
It may also be helpful to review the page life-cycle and events.
Is it possible, with the ASP.NET Ajax library (Sys....) to add controls to the page. For example in JQuery I would perform
$("#mydiv").append($("#anotherdiv input"));
Or something similar. I want to do this without wrapping everything in an UpdatePanel if possible, preferably through clientside scripting. But I have a feeling this will confuse the ViewState.
N.B. This isn't a dupe of this post, which is about something different.
I'm closing this as it is possible, however it's fiddly. Chapter 10 of ASP.NET AJAX in Action covers it a little. Without partial postback though it's impossible
Your correct--it would confuse the viewstate as all the controls need to be on the page during or before the OnInit() method, as far as I can remember.
Yet, you may still be able to use some jQuery/Ajax to pull back the rendered control. Say, for instance, you had a "helper" page, "MyControlsOutput.aspx", and on that page, you had your control embedded into it, ie "". Then, you could, in theory, use jQuery to query the MyControlsOutput.aspx page, and return the responsetext to your page. Again, it would not be in your ASP.Net page's control collection, nor would it have any clue about your viewstate. So, this is probably not what you're looking for, but, it was just a thought.
...While writing the above, I did a quick Google search for "asp.net ajax load control". See if this may help (you may have already seen this, sorry if that's the case):
http://weblogs.asp.net/sanjeevagarwal/archive/2008/07/22/Dynamically-create-ASP.NET-user-control-using-ASP.NET-Ajax-and-Web-Service.aspx
It's a similar concept, but it looks like they are using ASP.Net's ajax calls, and loading it into the page's control collection, and letting it use the page's viewstate as well. Couldn't hurt, eh? :)
Hope that helps a little bit. Good luck.
I am looking to make a web control where I can register client startup scripts inline with my aspx because I hate registering in the codebehind!
An example of what I have so far:
<Ben:StartupScript runat="server">
var form = document.getElementById("<% =form1.ClientID %>");
</Ben:StartupScript>
Currently, I am overriding the OnPreRender method of the control, rendering the contents of the control to a string and then manually registering that string as a startup script using ClientScript.RegisterStartupScript on the Page. I also override the Render method in order not to render the control. I should also note that I have the ParseChildren attribute set to false and the PersistChildren attribute set to true.
All seems to be working well, but my control allows other web controls inside it (such as Button). Apart from being unintuitive, this can result in runtime errors. I would love to be able to clear the controls but this is impossible given the <% ... %> code block.
So, is it possible to prevent developers from embedding child controls whilst still allowing code blocks?
Also, is this idea any good or is it fundamentally flawed? Lol.
Thanks a bunch,
Ben
it sounds like a good idea, but if you spend too much time fighting the inherited/default behaviors then it may be more trouble than it's worth
if this is a one-shot issue, a cheap-hack solution is to just directly embed your scripts in the header of a master page ;-)
on the other hand, allowing developers to embed their own scripts as children of your web control might be useful
If you are using master pages, add another control in your section. That way you can easily add css/js to your headers in your child pages.
ClientScript.RegisterScript is mostly for user/server controls,