ASP.NET AJAX

Firefox 3 ignores cache control http headers - security risk for online apps!

Tim Huffam — Fri, 26 Sep 2008 03:17:40 GMT

If a user, using Firefox 3, signs out of a web site and does not close the browser, anyone else using that browser subsequently can view the content of pages loaded by the previous user (eg in an internet cafe, or any place where workstations are shared eg universities) - exposing private/confidential data.

This only affects HTTP post requests (not gets) and only Firefox version 3 - earlier versions (1.5, 2 etc), and IE, are not affected.

The main points are:

This is definately a bug: a violation of RFC 2616, section 14.9 that states "The Cache-Control general-header field is used to specify directives that MUST be obeyed by all caching mechanisms along the request/response chain".
Some companies who deem this a significant hole in their security have chosen to block requests from Firefox 3 (eg they deem it their responsibility to secure their customers private and confidential data to the best of their ability).
This bug has been registered with the Mozilla dev team, but currently (as of 26 Sept 2008) has a status of unconfirmed.

VS2008 Javascript debugging error: The breakpoint will not currently be hit. No symbols have been loaded for this document

Tim Huffam — Sun, 17 Aug 2008 22:04:24 GMT

When trying to debug javascript using Visual Studio 2008 there a couple of things you need to do first - otherwise it (debugging) will not work and you'll get the following error when you hover over breakpoint in your javascript:

The breakpoint will not currently be hit. No symbols have been loaded for this document.

Note that this is only for debugging using IE (6) - not sure about other browsers/versions.

Within IE go into Tools - Internet Options - Advanced tab and make sure the 'Disable Script Debugging' is unchecked.
Make sure you have a breakpoint in your javascript.
Start debugging your web app in VS.
Within VS select menu item Debug - 'Attach to Process...'
On the Attach to Process dialog, select the row which has explorer.exe for your app (the Title column will have you page title on it), then click Attach.

That's it - when your breakpoint is reached the VS debugger will be triggered.

HTH
Tim

ASP.NET 3.5 controls not being rendered

Tim Huffam — Wed, 09 Jul 2008 10:50:56 GMT

For some reason some controls/tags within ASP.NET do not always get rendered/passed to the client.

This has happened to me on a number of occasions. It seems limited to <style> and <script> tags - but happens for both raw HTML (within the aspx designer) and dynamically created tags (eg using new HtmlGenericControl("style")...).

This is happening to controls/tags within AJAX updatepanels within, webforms and usercontrols.

Sometimes I can work around this by simply placing these controls/tags some where else within the page structure. But the most consistent way to get around this issue is to place a non-blanking space before the tag eg:

 <style>...

Another half-baked solution hit's the road ;-)

Update:

After some investigation, I have found a not-so-half-baked solution - for getting javascript loaded and run on a page during an AJAX postback...

The solution is to not try and add a script tag by adding it to a control within the page - but rather use the ASP.NET AJAX ScriptManager class's RegisterStartupScript() method. There are two overloads for this, one loads/registers the script and runs it just once (initial page load) and the other on each asynchronous postback (the latter suited my needs).

HTH
Tim

Javascript error using Telerik controls with ASP.Net: Error: 'Telerik' is undefined

Tim Huffam — Tue, 08 Jul 2008 21:03:48 GMT

The following javascript error occurs when trying to use the Telerik controls and you haven't updated your ASP.NET (2.0) web.config file correctly.

Error: 'Telerik' is undefined

To fix make sure the following lines are within the <system.web> section of your web.config file:

In my case I was missing the ScriptResource.axd line. Also, you only need the ChartImage.axd line if you're using the chart control.

HTH
Tim

ASP.NET event firing twice

Tim Huffam — Mon, 23 Oct 2006 03:27:00 GMT

This seems to be a very common problem where by your event handler method gets run twice.

It is caused by VS.NET inserting 2 wireup of the event handler:

- once in the aspx (HTML) eg: <asp:Button ... OnClick="btnTest_Click" />

- and once in the VS.NET generated section (InitializeComponent) eg:
this.btnTest.Click += new System.EventHandler(this.btnTest_Click);

The easiest solution, imo, is to simply remove the "OnClick..." HTML markup from the .aspx page.

Eg change this:
<asp:Button ID="btnTest" runat="server" Text="Test" OnClick="btnTest_Click" />

To this:
<asp:Button ID="btnTest" runat="server" Text="Test" />

Rebuild, and bingo! - 1 event per click.

HTH

Tim

Manually configure a web app dir for a specific version of the .NET framework

Tim Huffam — Fri, 04 Aug 2006 00:24:00 GMT

In some cases you may want or need to change the version of .NET that a particular web application directory uses. Normally this is done via the ASP.NET tab on the IIS properties page for the web app, however it can also be done manually at the command line...

CD into the dir containing the version of .NET that you require eg: C:\WINDOWS\Microsoft.NET\Framework\v1.1.4322
Run aspnet_regiis.exe specifying the name of the dir you want this set against.
eg aspnet_regiis.exe -s W3SVC/nnn/ROOT/xxx (where nnn is the web site identifier and xxx is the dir name)
eg aspnet_regiis.exe -s W3SVC/1/ROOT/MySampleApp

It's that simple.

Atlas web site templates missing from "My Templates" after Atlas installation

Tim Huffam — Thu, 25 May 2006 06:46:00 GMT

If you've just installed ASP.NET Atlas, and have started up VS2005, clicked File - New - Web Site...

..but, hang on... the "Atlas Web Site" template isn't there (as it should be according to the 'Setup your environment' section of the Atlas setup).

In my case it appears that the original installation either had a problem (although I don't remember any issues at the time) or some how corrupt the templates or lost reference to them.

Well all's not lost. To fix I did the following:

Open Windows Explorer and go to the Atlas dir (eg C:\Program Files\Microsoft ASP.NET\Atlas\v2.0.50727).
Double-click on the file: ASPNETAtlas.vsi. This will run the template installation.
Accept the default settings and click Next then Finish.
After clicking Finish, it will probably popup and error dialog stating "File exists - An item with the name ASPNETAtlasWebApplicationVB.zip already exists. What would you like to do?" Select "Overwrite the file with the same name" and click OK.
Click Close.

HTH

Tim