Talk about P&P Web Client Software Factory on Toronto Architecture User Group meeting

Developing modular web applications is a popular topic in development communities especially after ASP.NET MVC framework has been introduced by Microsoft. However ASP.NET MVC is not the first and only framework that can help on that way.

I'll be talking about building modular enterprise-class modern web applications with the help of MVP design pattern and Microsoft Patterns and Practices Web Client Software Factory framework on the next meeting of Toronto Architecture User Group on Thursday October 29th. To attend please register online here.

Problem with Internet Explorer 8 Debugger on Windows 7

I continue to evaluate Windows 7 after upgrading from Windows Vista and share some experience (mostly bad of course, so people would not step on the same problem again). As I mentioned before, overall upgrade was smooth and mostly everything works OK. However time to time I stumble upon some really annoying problems that did not exist on Windows Vista and therefore need to be solved for Windows 7 from scratch.

One of the recent problems was Daemon Tools not working on Windows 7 and it was solved by installing Magic Disc. Now there is one more thing: after upgrading to Windows 7 I am not able to use IE8 Debugger. When I pressed F12 the Debugger icon appeared on the task bar but I can not switch to its window: it's not visible.

So obviously I searched over the Internet and luckily there was one post on Stack Overflow (apart from those guessing about a window being outside of the screen) that suggested that there may be some wrong setting in Windows registry. And there are some registry keys related to IE8 debugger! So the solution was to remove WindowsPos, Pinned and UseDevToolsDebugger keys from the [HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\IEDevTools] section. That completely solved the problem.

Unfortunately I can not tell whether those keys existed in Windows Vista and were incompatible with Windows 7 or their values have been incorrectly modified during the upgrade. But after removing them and starting IE8 debugger they haven't appeared again. So probably they are not needed anymore.

How to map .ISO file to a drive in Windows 7

So, recently I have upgraded my laptop from Windows Vista to Windows 7. The upgrade process was straight forward and flawless and everything so far was OK except one thing: the Daemon Tools that I've been using for mapping .ISO image files since 2004 on various Windows systems refuses to work on Windows 7. Even Windows 7 compatibility mode does not help: Daemon Tools manages to recognize Windows 7 anyways. Luckily there is another tool that provides with absolutely the same functionality and also free: Magic Disc. It works under Windows 7 flawlessly and really makes my life easier: no need to burn ISO files on CD/DVD anymore.

ASP.NET user name availability check using WCSF Validation Bundle

An average web site offering membership and protected content for its members requires users to sign up by visiting a sign-up or register page that allows a user to enter some information and create an account. A couple of pieces if information that users are commonly asked to enter are a User name or Login name and user's email. One potential problem with such user input is checking that entered login name and/or email address are available for registration and haven't been used by other users. When it's the case multiple attempts of entering available values can be very annoying and frustrating for users even making them to refuse registration on a web site. So improving user experience when validating login name and email is quite an important task.

How to set programmatically a value of a watermarked TextBox via JavaScript

There is an updated version of the article for the latest Ajax Control Toolkit release: http://blog.turlov.com/2010/05/how-to-set-programmatically-value-of.html

If you use ASP.NET AJAX and AJAX Control Toolkit you may find it useful to decorate some of your TextBox controls on a page with a TextBoxWatermark AJAX extender control from the AJAX Control Toolkit. It's fairly easy to use and a nice tool for improving both the page look and user experience. However if you need to set a value of a TextBox decorated with the TextBoxWatermark extender programmatically via JavaScript on the client-side you may notice that the behavior of the watermarked TextBox is different. If you use the regular way to set a value like this:

$get(textBoxId).value = someText;

then the value displayed in the TextBox on the page will change to the set value but the watermarked look will still be present and other AJAX Control Toolkit TextBox extenders (like a Calendar extender, for instance) will not recognize the new value. This happens because the TextBoxWatermark extender can not recognize and intercept your JavaScript operation since it's designed to serve user interactions. However there is a correct way of programmatic access to the TextBox's value. We modify the code above like that:

var textBox = $get(textBoxId);
if (textBox.AjaxControlToolkitTextBoxWrapper) {
    textBox.AjaxControlToolkitTextBoxWrapper.set_Value(someText);
}
else {
    textBox.value = someText;
}

The explanation is that most of the TextBox extenders from the AJAX Control Toolkit including a TextBoxWatermark extender use a special proxy class AjaxControlToolkitTextBoxWrapper to manipulate with the input elements. The proxy adds a special property AjaxControlToolkitTextBoxWrapper to the input element that contains a reference to itself allowing to access the value of the input element correctly. Similarly, if you need to get a value of a watermarked TextBox you do it like this:

var textBox = $get(textBoxId), text;
if (textBox.AjaxControlToolkitTextBoxWrapper) {
    text = textBox.AjaxControlToolkitTextBoxWrapper.get_Value();
}
else {
    text = textBox.value;
}

New version of ASP.NET AJAX Control Toolkit released

The new release of ASP.NET AJAX Control Toolkit is available for download. Bertrand Le Roy has written a very informative post about it.

What I particularly like in this new release is that the Color Picker extender is now included in the Ajax Control Toolkit. Hooray!

Along with the new Toolkit release there come a whole bunch of new tutorials and videos. Among them there are this particularly nice tutorial about the Color Picker extender and another excellent video tutorial by Joe Stagner. Thank you folks for such a great job!

What that means for the Color Picker Extender users is that they don't have to download it separately from Codeplex anymore because it is included in the Ajax Control Toolkit. For those who cannot yet switch to the new version of ACT the original Color Picker Extender control will continue to be available on Codeplex. During the next few days I will prepare and upload a new release synced up with the Ajax Control Toolkit.

It is very educating to read people's opinions about the new release of ACT in response to blog posts and on Codeplex. In general, the responses are positive, but occasionally there are some complaints, mostly about little things.

I would like to remind everybody that Ajax Control Toolkit is a completely community-based initiative (with, of course, the initial kick-off help from Microsoft) and people who work on it take time out of their personal calendars so let's be more tolerant and if you've come across something really bad please use the Issue Tracker.

As I mentioned before, I specifically was interested in reading responses about the ColorPicker.  Interestingly, all the complaints were about its look and feel, not about functionality. I admit that the UI it provides is rather simplistic but here is my question back: why don't you all take some time and come up with feedbacks and suggestions on what can be improved?

Since the ColorPicker was publicly available on CodePlex it's been downloaded more then 2000 times (and I don't count downloads of ACT source code) and only a few people suggested something about improving it. I take it as everybody has been satisfied.

Now that the CPE is a part of the ACT and has a bit more visibility I suggest that people who have suggestions or concerns please don't hesitate to speak up.

Survey: Ajax usage among .NET developers

If you haven’t already and you are a .NET developer, please take a couple minutes and answer this survey, whether you use Ajax or not. There are a number of Ajax surveys around, but this is the only one that focuses on .NET developers.

The survey:
http://www.zoomerang.com/Survey/?p=WEB22973CYKW2H

Enabling a WCSF solution for sub-Web Application Project

If in your Web Client Software Factory (aka WCSF) solution you use Web Application Project (as opposed to Web Site Project) for your web site you are able to use a so called sub-Web Application Project in order to further modularize your web application.

If you created a WAP WCSF solution from scratch this option will be available. If, however, you converted your Web Site WCSF solution to WAP WCSF solution or upgraded from the previous version of WCSF this option may not appear when you are trying to add a new business module to your solution.

Visibility of the "Create as sub-Web Application Project" checkbox depends on one single property of a solution file and if you don't see the checkbox open the .sln file with any text editor and check out that it contains the follwoing content:

  GlobalSection(ExtensibilityGlobals) = postSolution
  ...
  IsWCSFSolutionWAP = True
  ...
  EndGlobalSection

Usually this section is located in the bottom of a .sln file and the red line is the key to solving the problem. If you don't see the line in your solution file simply add it and reload the solution in Visual Studio. Problem solved.

How to Improve ASP.NET UpdatePanel Performance

Since ASP.NET AJAX UpdatePanel was first introduced it has earned a strange mix of reputation. From one hand it has become a tool of first choice for many ASP.NET developers who wanted an easy way of introducing an AJAX-like behavior for their ASP.NET web apps. From another hand it has earned a lot of criticism from seasoned web developers because of certain performance consequences associated with complex usage scenarios.

Well, everything may be good and may be evil based on how we use it. From my experience consious and judicious use of UpdatePanel is the key to saving its benefits and avoiding potential problems.

Below I suggest a number of rules that help achieving better results when using UpdatePanel.

• Avoid automatic refreshing of UpdatePanel; always stay in control of which UpdatePanel and when refreshes: set UpdateMode property to Conditional (the default value is Always).
  
  
• Minimize the content of the UpdatePanel: the <ContentTemplate> should only include controls that are neccessary to refresh. For instance if user input requires server-side validation include only an error message mark-up in the UpdatePanel and leave the rest of the form outside.
  
  
• Try to keep the partial postback trigger controls outside of their respective UpdatePanels unless its neccessary to change their markup.
  
  
• Try to stick to a simple rule: one trigger for one UpdatePanel. If you need to refresh multiple UpdatePanels during one request add a trigger control to only one of those UpdatePanels and refresh the others programmatically in an event handler on the server. The idea is to avoid uncontrollable refreshing of unnecessary UpdatePanels.
  
  
• Since ViewState is updated with every partial postback request turn the ViewState off on a page that contains the UpdatePanel wherever possible or store the ViewState on the server to avoid transferring it forth and back with every async request.
  
  
• Since Page runs through its lifecycle during every partial postback and executes methods like Page_Load or Page_PreRender make sure that logic that is unneccessary for refreshing UpdatePanel is not executed by wrapping it in if(!ScriptManager.IsInAsyncPostBack).


• If you use UpdatePanel event handlers like Init, Load, PreRender and Unload make sure that code inside these event handlers does not execute unless neccessary by checking Page.IsPostBack and ScriptManager.IsInAsyncPostBack properties.
  
  
• If you trigger an UpdatePanel programmatically from the client-side (via JavaScript) make sure that its event handler check for the event trigger value using Request.Params["__EVENTTARGET"] ot avoid unnecessary execution path.
  
  
• If you programmatically update Page's Header (Title, etc.) or other Page's content that is outside UpdatePanel make sure that this code never gets executed during partial postbacks. First of all its not neccessary since page does not refresh but also it may be dangerous because the content may not be handled properly by a browser.

Conclusion

There may probably be more tricks and tips regarding usage of UpdatePanel but those mentioned above have been proven by real exeprience. I would also recommend understanding how UpdatePanel works behind the scene and never hesitate using Fiddler to investigate what your web app's doing.