When I call a page with AJAX, everything goes fast and well. But if I have a page (for testing purposes) with the following code:
for(int i = 0; i < int.MaxValue; i++)
{}
the page loading is longer, which is obvious. But then, when I load a page that only sets a text on a label, it takes longer (about 5 seconds), but this ain't the case if I call this page before calling the test page (with the for loop).
So, all the loading goes fast, except when I call the test page. From there on every page loads slow. How come?
If that for...next loop is in the pageload of your page, ALL ajax queries will have to run that same loop; you should put any long-running processes inside a this.IsPostPack == false if statement, and then persist that data in viewstate if you need it during subsequent postbacks.
I found the solution. It was bad programming. With AJAX I was loading Web User Controls (ascx files). I saved the controls in the ViewState and in my page load I loaded these controls again. So per page load the previous user control was loaded. By removing this method in the page_load my problem is solved.
Thanks for the effort though.
Related
Why we set master page in Page_Init event. We have other events in page.
For me one reason could be that master page does not have Pre_Init and other could be that Init of Page occurs before master page Init. Correct me if I'm wrong.
Master page is a UserControl. During Page.Init event, all the controls on the page are initialized(Control.Init is called). That's why the master page needs to be applied in Page.PreInit
Masterpage doesn't have PreInit method.
Master pages inherits:**System.Web.UI.MasterPage** and as per the design of this MasterPage class no such PreInit event is defined for this class.
Master pages are derived from Control class as seen in below hierarchy:
System.Object
System.Web.UI.Control
System.Web.UI.TemplateControl
System.Web.UI.UserControl
System.Web.UI.MasterPage
Therefore as can be guessed now, Master pages behave and in essence are treated like a control and have events similar to other asp.net server control
Because all things that 'dynamically' modify page controls have to occur there. This is where the page is rebuilt (form objects) with out request. Then things like page_load occur, after all objects are made.
Winforms analogy - if you are familiar with that - page_init is analogous to the InitializeComponent in the New (NOT REALLY SAME - just analogy please).
Only due to the nature of the web (at least round-tripping to the server), it can't possibly work like winforms (or WPF or even a SPA web app with a js/DOM UI and webapi backend) so has to rebuild the form's objects EVERY request.
Why does only the PAGE have page_init and not master page? Well as prateek says, but in addition, the rebuild of the page has to be control from just one spot. There is just one request. Controls can init, too as the page init process calls them in turn.
You have asked a question with a complicated answer.
Here is a good chart of what's going on...
http://www.codeproject.com/KB/aspnet/ASPDOTNETPageLifecycle.aspx
(source: codeproject.com)
Note how the postback data is loaded into the controls BEFORE the page_load, too - this is why it's too late to do anything big in the page load. You can't possibility get anything back from the user that was changed there (unless you go right to the postback data). The picture shows how ASP tries to 'fake' an event - driven UI on a client/server web architecture (e.g., 'event related logic' calls your 'events'). There is no such thing in client/server asp UI!
As a master page is the default screen throught the application ,it should be initialized first before the child pages.In order to get initalized earlier it is done in pre_init where the master page is loaded.later in Init() all the child pages are loaded regarding to that master page.
During the ASP.NET page life cycle, the initialization is also included on the master page. This is where the design and all the controls that are on the master page will be available before the page is loaded, which will be the "Load" phase of the page life cycle. If the master page is not initialize, you would get a page with no design, except the information on the page.
"During page initialization, controls on the page are available and each control's UniqueID property is set. A master page and themes are also applied to the page if applicable. If the current request is a postback, the postback data has not yet been loaded and control property values have not been restored to the values from view state."
https://msdn.microsoft.com/en-us/library/ms178472.aspx
I need to be able to detect when an entire page is loaded. The page has JavaScript that executes when you browse to it as well. And I must wait for that to finish loading as it adds HTML Elements to the page.
I have tried the below event. But this is trigger when the main page loads and doesn't care about the javascript.
browser.LoadingStateChanged
So I also tried count these to know when all the frames on a page where loaded. But it still wasn't spot on.
browser.FrameLoadStart += OnFrameLoadStart;
browser.FrameLoadEnd += OnFrameLoadEnd;
Any suggestions
Ended up using javascript to wait for element to display and then continue
I have html form which default value is display:none.
Im showing it with jquery.
There is button with C# code behind. When its executing page is reloading and my form is disappearing(display:none).
How i can execute c# code without page reload ?
Your c# code is server side and the page reloads to be able to call it. If you don't want that you'll need to use some AJAX.
See this tutorial: http://www.asp.net/web-forms/videos/aspnet-ajax/how-do-i-make-client-side-network-callbacks-with-aspnet-ajax
Is all of your code in the Page_Load section? Each time you make a callback the Page_Load runs. To stop certain things from happening each time you make a callback you can put them in something like
if (!Page.IsCallback && !Page.IsPostBack)
{
//this code will only be run the first time the page is loaded.
}
I need to populate 4 GridViews on an aspx page, but I only bind a datatable to one of them on page load. I need to pupulate the other 3 after page load.
does anyone know the best way to do this using ajax ?
Currently I'm using javascript to __doPostBack on a button that pupulates the 3 GridViews but unfortunately this forces a full page load even when using an update panel. I need the page to load, and then populate the GridViews as the datatables are returned.
any suggestions would be much apreciated.
The way you are doing it should work ok, although using jquery to populate a div via the $("#targetDiv").load("contentUrl"); function may be a cleaner way to do it. Anyway, in order to get your current implementation working, there could be a few things you want to look at:
I assume EnablePartialRendering is true on your ScriptManager (always worth checking!).
Make sure the eventTarget for the __dopostback call is set up as an async trigger for your update panels or that it is inside the UpdatePanel if you are only using one UpdatePanel. (See here for details)
Try returning false from the javascript code that executes in the onclick event handler if you have attached this to a button, to make sure the form is not being submitted normally by your browser when you click the button.
If I understand the question properly, you want the data to load after the page is in the browser. If this is the case, then you can fire an event with JavaScript when the page loads on the client.
One method I've used is to put a hidden (with CSS, not any property) button on the page and 'clicking' it with javascript. The event of the button click event will need to be wired in the page's code. Also the button would have to be in an update panel that either contains the grids you want to be bound or has the appropriate triggers to cause them to reload.
You might look at JQuery to get manage when this code gets fired. The $(document).ready(function(){ /* Your code here... */ }); method will fire after the entire DOM is available, which is faster than waiting on the entire page to load (images and so forth).
I have a method thats run on a button click, with 4 labels. What I need to do is update a label after each block of code executes. I've tried threading, updatepanels, etc and can't seem to get anything to work. I thought the timer would work, but it only ticks when you're not inside a method. The code looks something like this:
private void SomeMethod()
{
label1.text = "Processing...";
AnotherMethod();
label1.text = "Done.";
label2.text = "Processing...";
AnotherAnotherMethod();
label2.text = "Done.";
//etc...
}
You have a misunderstanding of how asp.net works. Your server code runs in response to a request from a browser for a complete html page. This is true even when all you really want to do is run some button click code. The entire page must be rebuilt from scratch anyway, even on postbacks. It's just the way web forms are designed.
As soon as the page is rendered to the browser, that instance of your page class is destroyed. On the next postback you'll start from scratch again, with the notable exceptions of the session, viewstate, and the application cache. Even the page's previous DOM instance in the browser is replaced.
So when you set the text property of the label you aren't directly updating anything visually in the browser. All you are doing is updating some temporary storage in your page class. As the last stage of executing your server code, all those temporary variables are used to render the completed html and the response is finally sent to the browser and shown to the user.
That should be enough information to give you an understanding of why your code doesn't behave as expected. It's running all of the code in the method before any of your property changes make their way to the browser. Therefore, the only thing the user sees is the final state of the operation.
Now ajax can complicate things a bit. When using an ajax control you might not be updating the entire page anymore, but the concept still applies: one request is made, and one response is received and used to update the entire context of the request. You can further muddle things if you have a lot of javascript in place to handle the result of the ajax request.
Unfortunately, there's no quick fix for the code you posted. You'll need to think about how this really works and decide how you want your page to flow.
Can you expose the 3 methods to client script and then call them sequentially from your client side code, when method1 finishes the client script would update the ui then call method2, and so on...