Early response termination when using an ASP.NET Master Page - asp.net

I have a page which needs to terminate execution of it's code (which is run at render) but not stop the execution of the MasterPage.
The problem is this,
page 'Default.aspx' uses the masterpage 'MasterPage1.aspx'. The code in Default.aspx checks a certain condition and if found to be true, Default.aspx needs to stop executing, but render the rest of the MasterPage.
I found that if I call response.end() in default.aspx, the rendering of the MasterPage is also terminated.
So what I am looking for is an alternative which stops execution in default.aspx, but still renders the rest of the MasterPage.
Thanks :)

Rather than returning a master page without any content, why not use Response.Redirect to go to an error page (which could have the same master page)?

You can use Server.Transfer() to go to a new page, and avoid a redirect.

Related

Master pages in asp.net ? Execution of Master pages?

In asp.net, i have taken one master page, 4 four child pages and one login page, which is not in a master page. My question is when a user login redirects to the page which is has master pages, is master page execute every time or only one time after login.
Master-page-engine is just part of total page life-cycle. (see for full list of taken actions there: http://blogs.thesitedoctor.co.uk/tim/2006/06/30/Complete+Lifecycle+Of+An+ASPNet+Page+And+Controls.aspx)
So short answer - yes, each time page derived from master is shown - master is executed.
A master page is executed every time a requested childpage has it as it´s parent.
So if you go to your loginpage without master and then redirects to a page with the master, the masterpage is executed once. If you later request another page with that master or the same page again doesn´t matter. The masterpage will be executed again.
Study the ASP Page lifecycle as the masterpage has some strange behaivor and acts mote like a subcontrol. You have to be a bit careful with some events.

Duplicate Script Managers

I'm working on an ASP.Net webforms app, and I've run into a unique issue. There is a script manager for an update panel on the MasterPage, as well as a script manager in a sub-page calling the master page. This as i'm sure you will note cause an exception to be thrown and crash the webapp.
I've tried programatically excluding the scriptmanager + update panel from the code as follows:
<% If Not (Result.RawURL.Contains("ExcludedPageDirectory") Then %>
<!-- all that code goes here -->
<% End If%>
However I think just the presence of the script manager tag in the source is causing the error. How would I programatically handle this?
A page can contain only one ScriptManager control in its hierarchy. To register services and scripts for nested pages, user controls, or components when the parent page already has a ScriptManager control, use the ScriptManagerProxy control (Source: MSDN)
You don't require a script manager again in the page if you have it in the master page.
Remove it and try
I ended up duplicating the master page and left out the update panel/scriptmanager code. This seems to have been the most elegant solution for the given situation. However I feel that the ScriptManagerProxy answer held the best possible solution had the duplication of the masterpage not been possible.

ASP.NET AJAX weirdness

Ok, I thought I understood these topics well, but I guess not, so hopefully someone here can clear this up.
Page.IsAsync seems to be broken. It always returns false.
But ScriptManager.IsInAsyncPostBack seems to work, sort of.
It returns true during the round trip for controls inside UpdatePanels. This is good; I can tell if it's a partial postback or a regular one.
ScriptManager.IsInAsyncPostBack returns false however for async Page Methods. Why is this? It's not a regular postback, I'm just calling a public static method on the page.
It causes a problem because I also realized that if you have a control with AutoPostBack = false, it won't trigger a postback on it's own, but if it has an event handler on the page, that event handler code WILL run on the next postback, regardless of how the postback occurred, IF the value has changed.
i.e. if I tweak a dropdown and then hit a button, that dropdown's handler code will fire. This is ok, except that it will also happen during Page Method calls, and I have no way to know the difference.
Any thoughts?
As Tjaart points out, Page.IsAsync has nothing to do with AJAX! See MSDN for a bit more info about IsAsync and see http://msdn.microsoft.com/en-us/magazine/cc163725.aspx for a fuller description of async pages].
Page methods are web services by a different name. The ScriptManager will emit the necessary JS boiler plate to make creating an XHR that invokes the web service very easy but that's all ScriptManager has to do with them really.
As the MSDN page states, ScriptManager.IsInAsyncPostBack will only be true if the request is in "partial rendering mode" so ScriptManager.IsInAsyncPostBack will be false when you are executing a page method because that request has not been spawned as a result of a partial postback (i.e. an UpdatePanel refreshing its contents).
Now it sounds like you are getting server side event handlers being executed as an apparent result of calling a page method from JS. AFAIAA, invoking a page method using javascript should not cause the page to go through its normal page lifecycle - so Page load, init etc. and these events should not be executing. So that is strange.
Suggestion: -
See Anz's comments and Dave's replies here encosia.
Could it be that you are having similar problems to Anz? i.e. The page method is invoked and but then your page is posting back immediatly after?
This is so because ASP.NET Ajax and ASP.NET Callbacks are two different things and are implemented differently. Unfortunately you have to use both Page.IsAsync and ScriptManager.IsInAsyncPostBack.
Page.IsASync probably returns whether the page was set as Async in the page directive
<%# Page Language="vb" Async="true" ...
The autopostback flag is so that you don't get a postback after every single control action, so the user can fill in an entire form and then only create the postback and trigger all the related code.
It's not really weirdness, they designed it this way so that the server side code will always be synchronized with the client side. So if you make a drop down list selection on the page and a postback occurs then that drop down list change executes it's own code along with the control that triggered the postback. You may want to read up more on the ASP .Net page lifecycle. it made things much more clear for me.

Page_Load Is not Hit in SubFolder Default.aspx after Redirect to that Page

I have a page that sites in a first level folder from my root called default.aspx.
I'm redirected to that page like as so:
I have an initial root Default.aspx that holds a login button
User clicks the login button and it redirects to Facebook Login
After logging in, Facebook redirects back to my first level Default.aspx (sits inside root\firstlevelfolder\Default.aspx)
The page_load is not being hit. This is a .NET 2.0 solution in VS 2008. The AutoEventWireup is set to true in the page directive.
Not sure why and have not seen this error before. Does it have something to do with redirecting to a non root-level .aspx page? This is probably something fundamental but I"m not sure what it is.
breakpoint in the first line of code
in my page_load
You're using a breakpoint. Double-check that Visual Studio is in debug mode and your browser is pointing to localhost:1234 (where 1234 is some random port number assigned by the VS web server). Also, try doing a simple Response.Write("Hello World") in Page_Load(), and see if anything prints out on the top of the page.
You said to try the trace in the root.
No. Try it in the page that you think that Page_Load isn't firing on.
Also, on StackOverflow, it is much easier for others to follow the conversation, and it makes for a cleaner post if you can reply to questions using the "add comment" feature. The reason I'm posting another answer is just in case you're not aware of the feature and you miss the comment. See the SO Community FAQ item regarding comments.
Put a Trace="True" in your <%# Page %> line in the "first level" Default.aspx. The part that you would want to look at is the second section - "Trace Information". See if there is a "Begin Load" item in that list.
Also, is your page inheriting from the System.Web.UI.Page object, or do you have a custome base page?
public partial class _Default : System.Web.UI.Page //or do you have a different object here?
{
...
}
Does Page_Load get hit if AutoEventWireup is false?
Does the page that you are redirecting to work if you hit it directly from your browser without an intermediate page that redirects you there? I don't think the cause of your problem has to do with the fact that the page is in a subdirectory.
If the trace is showing that Begin Load is firing, then what methodology are you using to determine that Page Load doesn't work?

ASP.NET master pages order of adding scripts

I have a master page that adds the jquery library via a registerclientscriptinclude:
Page.ClientScript.RegisterClientScriptInclude(this.GetType(),
"JQuery",
Page.ResolveUrl("~/Scripts/jquery-1.2.6.min.js"));
In a page that uses that master page I want to include a script that depends on jquery:
Page.ClientScript.RegisterClientScriptInclude(this.GetType(),
"jqplugin1",
Page.ResolveUrl("~/Scripts/jquery.plugin1.compressed.js"));
This causes a problem because the page's client scripts are written first and then the master pages client scripts (causing the plugin to complain that "jquery" is undefined).
Is there anyway to control the ordering of client script includes? Alternatively any recommendation on how best to control this (temporarily the master page is just including everything... but that's not going to work long term).
since master page is like a control embedded in a page, you can add these scripts towards the end of the page cycle, the control would fire first and then page, so your page would be fine.
You could re-include the jQuery library in the page, if it's already there it will simply override it, if not it will be added.

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