The blog of dlaa.me

A number of years ago, the product team I was on spent a lot of team analyzing large log files. These log files contained thousands of lines of output tracing what the code was doing, what its current state was, and gobs of other diagnostic information. Typically, we were only interested in a handful of lines - but had no idea which ones at first. Often one would start by searching for a generic error message, get some information from that, search for some more specific information, obtain more context, and continue on in that manner until the problem was identified. It was usually the case that interesting lines were spread across the entire file and could only really be understood when viewed together - but gathering them all could be inconvenient. Different people had different tricks and tools to make different aspects of the search more efficient, but nothing really addressed the end-to-end scenario and I decided I'd try to come up with something better.

TextAnalysisTool was first released to coworkers in July of 2000 as a native C++ application written from scratch. It went through a few revisions over the next year and a half and served myself and others well during that time. Later, as the .NET Framework became popular, I decided it would be a good learning exercise to rewrite TextAnalysisTool to run on .NET as a way to learn the Framework and make some architectural improvements to the application. TextAnalysisTool.NET was released in February of 2003 as a fully managed .NET 1.0 C# application with the same functionality of the C++ application it replaced. TextAnalysisTool.NET has gone through a few revisions since then and has slowly made its way across parts of the company. (It's always neat to get an email from someone in a group I had no idea was using TextAnalysisTool.NET!) TextAnalysisTool.NET is popular enough among its users that I started getting requests to make it available outside the company so that customers could use it to help with investigations.

The effort of getting something posted to Microsoft.com seemed overwhelming at the time, so TextAnalysisTool.NET stayed internal until now. With the latest request, I realized my blog would be a great way to help internal groups and customers by making TextAnalysisTool.NET available to the public!

You can download the latest version of TextAnalysisTool.NET by clicking here (or on the image above).

In the above demonstration of identifying the errors and warnings from sample build output, note how the use of regular expression text filters and selective hiding of surrounding content make it easy to zoom in on the interesting parts of the file - and then zoom out to get context.

Additional information can be found in the TextAnalysisTool.NET.txt file that's included in the ZIP download (or from within the application via Help | Documentation). The first section of that file is a tutorial and the second section gives a more detailed overview of TextAnalysisTool.NET (excerpted below). The download also includes a ReadMe.txt with release notes and a few other things worth reading.

The Problem: For those times when you have to analyze a large amount of textual data, picking out the relevant line(s) of interest can be quite difficult. Standard text editors usually provide a generic "find" function, but the limitations of that simple approach quickly become apparent (e.g., when it is necessary to compare two or more widely separated lines). Some more sophisticated editors do better by allowing you to "bookmark" lines of interest; this can be a big help, but is often not enough.

The Solution: TextAnalysisTool.NET - a program designed from the start to excel at viewing, searching, and navigating large files quickly and efficiently. TextAnalysisTool.NET provides a view of the file that you can easily manipulate (through the use of various filters) to display exactly the information you need - as you need it.

Filters: Before displaying the lines of a file, TextAnalysisTool.NET passes the lines of that file through a set of user-defined filters, dimming or hiding all lines that do not satisfy any of the filters. Filters can select only the lines that contain a sub-string, those that have been marked with a particular marker type, or those that match a regular expression. A color can be associated with each filter so lines matching a particular filter stand out and so lines matching different filters can be easily distinguished. In addition to the normal "including" filters that isolate lines of text you DO want to see, there are also "excluding" filters that can be used to suppress lines you do NOT want to see. Excluding filters are configured just like including filters but are processed afterward and remove all matching lines from the set. Excluding filters allow you to easily refine your search even further.

Markers: Markers are another way that TextAnalysisTool.NET makes it easy to navigate a file; you can mark any line with one or more of eight different marker types. Once lines have been marked, you can quickly navigate between similarly marked lines - or add a "marked by" filter to view only those lines.

Find: TextAnalysisTool.NET also provides a flexible "find" function that allows you to search for text anywhere within a file. This text can be a literal string or a regular expression, so it's easy to find a specific line. If you decide to turn a find string into a filter, the history feature of both dialogs makes it easy.

Summary: TextAnalysisTool.NET was written with speed and ease of use in mind throughout. It saves you time by allowing you to save and load filter sets; it lets you import text by opening a file, dragging-and-dropping a file or text from another application, or by pasting text from the clipboard; and it allows you to share the results of your filters by copying lines to the clipboard or by saving the current lines to a file. TextAnalysisTool.NET supports files encoded with ANSI, UTF-8, Unicode, and big-endian Unicode and is designed to handle large files efficiently.

I maintain a TODO list with a variety of user requests, but I thought I'd see what kind of feedback I got from releasing TextAnalysisTool.NET to the public before I decide where to go with the next release. I welcome suggestions - and problem reports - so please share them with me if you've got any!

I hope you find TextAnalysisTool.NET useful as I have!

The 10606 release of the AJAX Control Toolkit introduced ToolkitScriptManager, a new class that extends the ASP.NET AJAX ScriptManager to perform automatic script combining. I blogged an overview of ToolkitScriptManager last week (including an explanation of what "script combining" is). This post will build on that overview to discuss some of the changes to ToolkitScriptManager in the 10618 release of the Toolkit.

The most obvious change is the addition of an optional new property: CombineScriptsHandlerUrl. Left unset, ToolkitScriptManager works just like before; setting CombineScriptsHandlerUrl specifies the URL of an IHttpHandler (feel free to use @ WebHandler to implement it) that's used to serve the combined script files for that ToolkitScriptManager instance instead of piggybacking them on the host page itself. Implementing this handler is simple: just use the CombineScriptsHandler.ashx file that's part of the SampleWebSite that comes with the Toolkit! :) If you look at how that handler works, the ProcessRequest method simply calls through to the ToolkitScriptManager.OutputCombinedScriptFile(HttpContext context) method which is public and static for exactly this purpose. OutputCombinedScriptFile does all the work of generating the combined script file and outputting it via the supplied HttpContext - in fact, this is the same method that ToolkitScriptManager now uses internally to output a piggybacked combined script file. Because adding a handler in this manner doesn't require modifying the server configuration, CombineScriptsHandlerUrl can also be used by people in hosted and/or partial trust scenarios.

At the end of my previous post, I mentioned two tradeoffs that were part of switching from ScriptManager to ToolkitScriptManager. Both of those tradeoffs are addressed by the 10618 ToolkitScriptManager - plus one more I didn't know about then and another that's implicit:

• Using CombineScriptsHandlerUrl incurs no unnecessary load on the server. One of the tradeoffs of the piggyback method for generating combined script files is that it involves a little bit of extra processing as part of the host page's page lifecycle that's not strictly necessary for the purposes of generating the combined script file. ToolkitScriptManager manages the page lifecycle processing to minimize the impact of piggybacking, but can't eliminate it all. However, using CombineScriptsHandlerUrl with a dedicated IHttpHandler doesn't involve any such overhead and helps keep things as efficient and streamlined as possible. The host page doesn't get reinvoked and the dedicated IHttpHandler does no more than it needs to.
• Using CombineScriptsHandlerUrl won't interfere with URL rewriting. Customers using URL rewriting with their web sites pointed out that the piggybacking approach to combined script generation might require them to revise their URL rewriting rules to account for the unexpected page requests with the special combined script request parameter. ToolkitScriptManager tries to be as easy to use as possible, so one of the nice things about setting the new CombineScriptsHandlerUrl property is that web site authors can choose whatever URL works best for them to be their combined script file handler, thereby avoiding conflict with existing URL rewriting rules.
• Using CombineScriptsHandlerUrl makes it more likely that cached script files will be reused. When piggybacking combined script URLs, the presence of the host page's base URL in the combined script URL means that any cached script files generated by page A will not be usable by page B (which has a different base URL). Of course, once the user's browser caches the combined script files for pages A and B, the cached versions will be used and there is no server impact - but page B won't benefit from page A's cached file even if the combined script files are otherwise identical. When pages A and B both use the same set of extenders and CombineScriptsHandlerUrl is specified, the combined script file URL generated by pages A and B will be identical (because the combined script file handler base URL will be the same for both) and therefore the combined script file cached by the user's browser for page A will be automatically used for page B as well. For web sites with common extender usage patterns (such as a TextBoxWatermark'd search box in the corner of every page), the caching benefits of CombineScriptsHandlerUrl could be significant.
• The URLs used to specify combined script files are considerably less verbose. Rather than including the full script name for every script in the combined script file (often upwards of 20 or 30 characters), the hexadecimal representation of their String.GetHashCode is used instead (8 or fewer characters). While the baseline combined script URL length has grown by a bit due to some other changes, by far the most significant source of URL length was the script names, so the new URLs are shorter and less likely to get long (even on pages with lots of extenders). This improvement applies whether CombineScriptsHandlerUrl is specified or not, so piggybacked URLs are shorter, too. Note: Because hash code collision is now possible (though extremely unlikely), there's a bit of code to detect that scenario and throw an informative exception. (Just change either of the script names slightly to resolve the collision.)

A handful of other fixes and improvements were made to ToolkitScriptManager for the 10618 release. Notably:

• The CurrentUICulture is now embedded in the combined script URL so that changing the browser's culture while viewing a site will properly update the culture of the site's extenders.
• ToolkitScriptManager's check for a script's eligibility to participate in script combining now includes a check for the WebResource attribute which is one of the things that ASP.NET's ScriptResourceHandler requires in order to serve an embedded resource. Consequently, an assembly's embedded resources without a corresponding WebResource attribute are no longer eligible for script combining (without needing to use the ExcludeScripts to explicitly remove them). This makes ToolkitScriptManager's behavior more consistent with that of ScriptResourceHandler.
• The "magic" request parameter for the combined script file changed from "_scriptcombiner_" to "_TSM_HiddenField_"/"_TSM_CombinedScripts_". _TSM_CombinedScripts_ is simply a rename of _scriptcombiner_, while _TSM_HiddenField_ now specifies the HiddenField that's used for tracking which scripts have already been loaded by the browser. This ID is implicitly available when piggybacking, but is not available in the CombineScriptsHandlerUrl case, so it has become part of the URL. For completeness, the new form of the combined script URL is now:
  .../[Page.aspx|Handler.ashx]?_TSM_HiddenField_=HiddenFieldID&_TSM_CombinedScripts_=;Assembly1.dll Version=1:Culture:MVID1:ScriptName1Hash:ScriptName2Hash;Assembly2.dll Version=2:Culture:MVID2:ScriptName3Hash

If you're already using ToolkitScriptManager and want to start using CombineScriptsHandlerUrl, but don't want to have to modify a bunch of ASPX pages to add the new property, you can take advantage of the fact that ToolkitScriptManager is now decorated with the Themeable attribute and can be customized by a .skin file as part of ASP.NET's Theme/Skin support. Adding CombineScriptsHandlerUrl to all the pages of the Toolkit's SampleWebSite was easy - I just added a ToolkitScriptManager.skin file to the existing web site theme and used the code <ajaxToolkit:ToolkitScriptManager runat="server" CombineScriptsHandlerUrl="~/CombineScriptsHandler.ashx" /> to set CombineScriptsHandlerUrl for the entire site.

ToolkitScriptManager is a handy way to enhance a web site with the AJAX Control Toolkit and it's gotten even better with the 10618 release of the Toolkit. We think ToolkitScriptManager offers some pretty compelling enhancements and we use it for all the AJAX Control Toolkit's sample content. We encourage anyone who's interested to give ToolkitScriptManager a try and see how well it works for them. As always, if there are any problems, please let us know by posting a detailed description of the problem to the AJAX Control Toolkit support forum.

Happy script combining!!

A short while ago we made available the 10618 release of the AJAX Control Toolkit. This release addresses a handful of user-impacting issues introduced by changes in the recent 10606 release and identified by the user community in the support forum and online issue tracker. Significant changes always have the risk of introducing problems so we do our best to find and fix them all before releasing. But for things that manage to sneak through, a targeted follow-up release is often a good way to fix annoyances quickly.

The release notes from the sample web site detail the improvements in the new release:

General fixes:

• Tabs: Resolved NamingContainer issues so that FindControl works as expected in Tabs.
• ToolkitScriptManager: Shorter combined script URLs and new HTTP handler support for generation of combined script files.
• Dependencies: Removed explicit reference to VsWebSite.Interop.dll and stdole.dll. They will not be automatically included in the web configuration files by Visual Studio.
• FilteredTextBox: Navigation, Control and Delete keys work fine in all browsers.
• Localization: Turkish, Dutch, and Traditional and Simplified Chinese language support added.

As always, it's easy to sample any of the controls right now (no install required). You can also browse the project web site, download the latest Toolkit, and start creating your own controls and/or contributing to the project!

If you have any feedback, please share it with us on the support forum!

PS - Last week I blogged an overview of the ToolkitScriptManager introduced in the 10606 release. ToolkitScriptManager has gotten even better in this release, and I'll be writing more about it later this week!

Note: Recent versions of ASP.NET AJAX include the ScriptManager.CompositeScript property which performs much the same functionality as discussed here. More information is available in the article Combining Client Scripts into a Composite Script.

 

Introduction

The 10606 release of the AJAX Control Toolkit includes ToolkitScriptManager, a new class that derives from the ASP.NET AJAX ScriptManager and performs automatic script combining.

What is meant by "script combining" and why is it desirable?

ASP.NET AJAX Behaviors are typically implemented by JavaScript (JS) files that are downloaded by the browser as part of the web page's content/resources (like CSS files, images, etc.). Each JS file typically contains a single Behavior, so if a web page uses lots of Behaviors, it's going to download lots of Behavior JS files. The cost to download a single JS file is fairly minimal, but when there are many of them on a page, the serialized nature of Behaviors (later ones may depend on earlier ones and can't be loaded until the earlier ones have finished) means that it may take a bit of time for all the JS a page needs to download to the user's browser. The time in question is typically on the order of milliseconds, but every little bit helps when you're looking to give users the best possible experience!

Script combining is beneficial because fewer JS files means fewer request/response operations by the browser - which translates directly into quicker page load times for users and less load on the web server. Furthermore, there will be less network traffic because the HTTP headers associated with each unnecessary request/response operation don't need to be transmitted (saving around 750 bytes for each combined script).

At the extreme, one could combine all (~40) the Behaviors in the Toolkit into a single, monolithic JS file (either manually or as part of the build process) and always send that file to the browser. While there are certain benefits to this, we chose not to do so for two main reasons: 1) the ASP.NET AJAX framework the Toolkit builds upon is an object-oriented framework and it's beneficial to maintain the mental/physical separation that comes from keeping each behavior isolated and 2) any page that used any part of the Toolkit would be forced to download the entire set of scripts in the Toolkit.

ToolkitScriptManager gives us the best of both worlds by combining exactly the relevant JS files used by each page into one file so the browser downloads only what's necessary for each page. ToolkitScriptManager's script combining is more than a simple concatenation of all the script files in the Toolkit; it's a dynamic merge of only the scripts that are actually being used by a page each time it's loaded by the browser. If a page has an ASP.NET AJAX UpdatePanel on it and additional scripts need to be sent as part of an async postback, then ToolkitScriptManager will automatically generate a combined script file containing only those scripts that the browser hasn't already downloaded.

ToolkitScriptManager automatically compresses the combined script file if the browser indicates it supports compression - achieving slightly better compression in the process because most adaptive dictionary-based compression techniques (like HTTP's GZIP and Deflate) tend to compress data better in one chunk than in multiple chunks (because the dictionary doesn't keep getting reset). The combined script file is cached and reused by the browser just like the corresponding script files would have been if ToolkitScriptManager weren't being used.

Basically, script combining effortlessly creates faster loading web pages - and happier users by extension!

How do I use it?

Simple: Just replace <asp:ScriptManager ... /> with <ajaxToolkit:ToolkitScriptManager ... /> in your ASPX page and you're done! (Of course, if you're not using the default namespaces "asp" and "ajaxToolkit", you'll need to substitute your own namespaces.) The scripts in the AJAX Control Toolkit are already enabled for combining, so it's really that easy!

ToolkitScriptManager derives from ScriptManager, so it can be substituted trivially. Configuration-wise, it exposes a single new property beyond what ScriptManager already has: bool CombineScripts. The default value of "true" means that scripts will be automatically combined - specifying the value "false" disables the combining. (Alternatively, just switch back to ScriptManager for the same result.)

How do I enable combining for my custom Behavior's scripts?

As a security precaution to prevent malicious users from taking advantage of ToolkitScriptManager to access embedded resources from unrelated DLLs, the new assembly-level ScriptCombine attribute must be used to indicate that a particular assembly/script is allowed to take part in the script combining process. By default, none of the scripts in an assembly without the ScriptCombine attribute will take part in script combining. Adding the ScriptCombine attribute to an assembly indicates that all of its scripts can take part in script combining and ToolkitScriptManager will automatically include the relevant ones when generating a combined script file. For finer control over individual scripts in an assembly, the ScriptCombine attribute exposes an ExcludeScripts property and an IncludeScripts property - both are comma-delimited lists of individual script files. As stated, when neither property is specified, the default behavior is that all scripts are combinable. Once the IncludeScripts property is set, only the scripts explicitly specified by it are combinable. The ExcludeScripts property excludes any listed scripts from combining (whether or not IncludeScripts is set). Of course, most people will simply add the ScriptCombine attribute to their assembly and the default behavior does what they want. (As mentioned above, Toolkit scripts are already enabled for script combining.)

How do scripts actually get combined? [Technical]

Script combining is a two-stage process.

The first stage takes place during the normal ASP.NET page lifecycle when ToolkitScriptManager overrides ScriptManager's OnLoad method to initialize its state and its OnResolveScriptReference method to find out when script references are being resolved. The initialization code in OnLoad consists of adding a HiddenField to the page and using it to track which scripts have already been loaded by the browser. The handling of OnResolveScriptReferences is a little more involved: the script reference is checked for combinability (i.e., does the assembly's ScriptCombine attribute allow the script to take part in script combining) and the script reference is changed to point to the URL of a combined script file. In this manner, all scripts that are part of the same combined script file get the same URL and the ScriptManager class outputs that URL to the page exactly once. Notably, because scripts may have a strict ordering, the presence of an uncombinable script in the middle of combinable scripts will result in two combined script files being generated (the first consisting of the scripts coming before the uncombinable script and the second consisting of the scripts after it).

The URL of the combined script file is currently of the form: .../Page.aspx?_scriptcombiner_=;Assembly1.dll Version=1:MVID1:Script.Name.1.js:Script.Name.2.js;Assembly2.dll Version=2:MVID1:Script.Name.3.js. What this means is that the ASPX page itself is referenced with the special request parameter "_scriptcombiner_" and a semicolon-delimited list of assemblies with a colon-delimited list of the required scripts from each of them. The strong name of the assembly is used to avoid potential confusion if multiple versions of an assembly are present and the ModuleVersionID (MVID) is used to ensure that any changes to the assembly itself automatically invalidate all combined script files that reference it. In this manner, recompiling one of the assemblies contributing to a combined script file will cause the new scripts to be downloaded by the browser next time the page is loaded.

The second stage of script combining takes place when the page is referenced with the "_scriptcombiner_" request parameter. ToolkitScriptManager overrides OnInit (one of the first parts of the page lifecycle) and uses that opportunity to generate the combined script file based on the value of the request parameter, outputs the combined script file to the browser, and stops further processing of the page lifecycle. Of note, the cache settings of the combined script file are set to the same values that the individual script files would have had if ToolkitScriptManager weren't being used and the combined script file is automatically compressed according to the browser's wishes. Similarly, any localized script resources for a script file that is in the process of being combined are loaded and sent to the browser as part of the combined script file. After all combined scripts are output, ToolkitScriptManager appends a small bit of script to the end of the file to update the page's HiddenField with the scripts that have just been added. In this manner, any additional scripts added during an async postback are automatically tracked by the page and subsequent async postbacks will know exactly which scripts have already been loaded by the browser.

Why piggyback a request parameter on the same page instead of using an IHttpHandler? [Technical]

ScriptManager uses ScriptResourceHandler (an IHttpHandler) to serve (uncombined) scripts, so it's natural to wonder why ToolkitScriptManager wouldn't do the same. The reason is that the AjaxControlToolkit DLL is often run in partial trust scenarios where it couldn't add such a handler to the system itself - and because we don't want people to have to modify their web.config file just to enable script combining. By making use of the same page for serving combined script files, ToolkitScriptManager offers a seamless experience that's simple to configure, simple to manage, and that works even for folks who don't have control over the web server that's hosting their content.

Are there any tradeoffs when switching to ToolkitScriptManager?

There are no significant tradeoffs that we know of, but there are a couple of implications it's good to be aware of. For one, the current combined script URL format is currently pretty verbose and can lead to unusually long URLs. While this hasn't been a problem so far, it will be easy to change the format in the future (with no impact to users) and we're already considering ways of doing so. Another thing to be aware of is that reusing the page to serve the combined script file means that there is some additional server processing that happens before/during the OnInit stage of the page lifecycle when processing a combined script file. (Though the additional work here is offset by the savings of not having to serve multiple JS files.) Again, this hasn't been an issue, but it's something to keep in mind if things behave differently after adding ToolkitScriptManager to a page.

So just how risky is it to switch to ToolkitScriptManager?

That's a loaded question [ :) ], but it's informative to note that all AJAX Control Toolkit sample pages (including the sample web site, automated tests, manual tests, etc.) have been converted over to use ToolkitScriptManager with only one issue: The Slider's SliderBehavior.js script uses a fairly obscure feature enabled by the PerformSubstitution property of the WebResource attribute that allows <%= WebResource/ScriptResource %> tags to be embedded in JS files and get resolved before the script is sent to the browser. This behavior isn't currently supported by ToolkitScriptManager (it will throw an informative Exception if it detects the presence of this construct), so the ExcludeScripts property of the ScriptCombine attribute on the AjaxControlToolkit DLL has been used to exclude the SliderBehavior.js file from being combined.

Summary

ToolkitScriptManager works seamlessly in every page of the AJAX Control Toolkit, so we encourage folks to give it a try if they're interested in the benefits it offers! As always, if you encounter any problems, please let us know by posting a detailed description of the problem to the AJAX Control Toolkit support forum.

Happy script combining!!

Earlier today we made available the 10606 release of the AJAX Control Toolkit. This release focused on addressing many of the most popular bugs and work items identified by the user community in the support forum and online issue tracker. We've also added some new functionality to the Toolkit that really improves the user experience for page authors and consumers alike!

The release notes from the sample web site detail the improvements:

General fixes:

• Design Mode support:
  • Tabs designer: Tabs control can be configured in the designer.
  • PageMethods in code-behind: Extenders that consume web services can now have PageMethods added to code-behind automatically when using the designer. A repair mode fixes existing PageMethods with incorrect signatures.
  • Control icons: Toolkit controls have more meaningful icons that show up in the Visual Studio Toolbox when the Toolkit DLL is added to it.
• Dynamic context: Toolkit extenders that consume web services can now pass additional context beyond what is used by the default web service signature.
• Validators and Toolkit extenders: Extenders that target TextBoxes with ASP.NET validators attached to them no longer interfere with the validation process.
• Animation support: Toolkit controls that build on top of PopupBehavior now have generic animation support built in.
• Script combiner: When the ToolkitScriptManager is used, Toolkit scripts are downloaded in a single, common JavaScript file instead of multiple files. This allows for faster downloads and fewer roundtrips. The combined file is generated dynamically depending on the controls being used on the page. All Toolkit sample pages use this new functionality.
• Events support: Toolkit controls fire events for core actions. This is in part to make plugging in animation easier and also to allow users to hook into the various Toolkit controls' behaviors and perform custom actions.
• Bug fixes: This release includes fixes for over 120 issues tracked in the Toolkit Issue Tracker representing over 750 user votes.
• Accessibility fixes: Slider and AutoComplete have support for high contrast and some controls like AutoComplete, NumericUpDown, CascadingDropDown and DynamicPopulate which issue XmlHttpRequests update a hidden DOM element to automatically refresh the JAWS screen buffer to reflect new data.

Control updates:

• MaskedEdit extender works well with the Calendar extender and the ValidatorCallout extender when targeting the same TextBox.
• AutoComplete supports scrolling in the fly-out, multi-word, first word default selection and it has animation built into it.
• ModalPopup fix for most common scenarios involving absolute and relative positioning.
• NumericUpDown has new Minimum and Maximum properties to restrict the range of numbers allowed.

Visual Studio Codename "Orcas" support:

• The Toolkit DLL works with ASP.NET AJAX Orcas Beta 1 DLLs and there are no breaking changes.

For more details about the Tabs designer, web service design-time enhancements, and script combining (along with some pretty pictures!), check out Shawn Burke's release announcement.

As always, it's easy to sample any of the controls right now (no install required). You can also browse the project web site, download the latest Toolkit, and start creating your own controls and/or contributing to the project!

If you have any feedback, please share it with us on the support forum!

PS - The public sample site hasn't been deployed quite yet (real soon now!), but the new Toolkit bits are up on CodePlex, so feel free to get them and start using them!

Yesterday, Microsoft announced its Surface product to much buzz and excitement. The demo videos I saw featured a "photos on a table" user interface that displayed a handful of photos sitting on the Surface. The interface allowed people to easily move the virtual photos around by touching them in the center and sliding them to a different location on the screen. By touching the corners instead, photos could be sized and rotated with ease.

It struck me that this interface would be pretty easy to replicate with Silverlight and I decided to do so as a learning exercise. I spent some time on this last night and tonight and came up with an application that looks like this:

You can click here (or on the image above) to play with the application in your browser. The code's quite simple; click here to download the source code and play around with it yourself! (To build the project, you'll want to use Visual Studio Orcas Beta 1 and the Silverlight Tools.)

Notes:

• When the application loads, it randomly lays out the sample photos. To interact with a photo, simply move the mouse pointer over the photo and click+drag on one of the yellow control elements that appears. The center element moves the photo around and the corner elements all rotate/resize it. Click on any part of a photo to bring it to the top of the pile.
• Without the snazzy Surface hardware support, this application doesn't support the Human Finger 1.0 input device. :) However, if you run it on a Tablet PC or hooked up to something like the Wacom Cintiq, you can get pretty close.
• As expected, Silverlight's XAML support makes this kind of interface pretty easy to build. I understand the Surface UI was written using WPF (Silverlight's big brother), so I suspect some of the techniques they used are fairly similar to what's being done here.
• The sample images are a few of my favorite wallpapers that come with Windows Vista. I have not included them with the code download because they're large and it's easy enough to copy them from your own %windir%\Web\Wallpaper directory. Or just use your own favorite images!
• I don't demonstrate it here (partly because I don't have a good nature video), but it would be easy to add video support so that each of the photos was a streaming video instead. Hum, maybe I'll do a follow-up post... :)

It's pretty obvious that XAML lets you do some pretty neat things with ease - I look forward to even more compelling new interfaces based on Silverlight and WPF!

Since getting involved with Silverlight and finding out the XPS document type WPF enables has XAML at its core, I've been wondering how Silverlight would do as a lightweight XPS viewer.

First, a bit of background: WPF is the Windows Presentation Foundation and represents a new approach to UI for Windows. XPS refers to the XML Paper Specification, a device-independent file format for flexible document representation (think PDF) that's part of Office 2007 and .NET 3.0. WPF offers rich support for displaying XPS documents via its DocumentViewer and XpsDocument classes (among others). Because the 1.1 Alpha release doesn't currently include the relevant classes, Silverlight wouldn't appear to be well suited for XPS document display at first glance...

However, Silverlight does have the Downloader class which includes support for packages (for the purposes of this discussion, packages are basically just ZIP archives). Since an XPS document is really just a package, and the core document format XPS uses is XAML, and Silverlight speaks XAML (well, at least a subset of it!), maybe it's not such a stretch to do XPS with Silverlight after all.

I thought it would be a neat exercise to try to write an XPS viewer with the publically available Silverlight 1.1 Alpha bits so I gave it a try and ended up with an application I call SimpleSilverlightXpsViewer:

Go ahead and click here (or on the image above) to play around with the application in your browser. If you find yourself wondering how it works, just click here to download the complete source code/resources and play around with it yourself! (To build the SimpleSilverlightXpsViewer project, you'll want to use Orcas Beta 1 and the Silverlight Tools.)

Of course, this is just a proof-of-concept application built on an Alpha platform, so there are some rough edges. :) Some notes are in order:

• I created my own XPS documents so I wouldn't have to worry about getting permission to use someone else's XPS documents. Office 2007 comes with a handy "Microsoft XPS Document Writer" printer driver that lets you create an XPS document from any application simply by printing to the XPS "printer" (which then saves the resulting output to a file you specify). I created the three sample documents this way: the "Intro" document came from a simple Word document, the "Blog" document came from my blog via IE7, and the "Site" document came from the Silverlight Forums via IE7 with a landscape page layout.
• Because the only kind of XPS document I've worked with is the kind the XPS printer driver outputs, there's a very good chance SimpleSilverlightXpsViewer won't understand the internal format of other valid XPS files. Remember, though, that I didn't set out to write an XPS file parser - I just set out to write a simple XPS viewer for Silverlight. :)
• The translation of "XPS XAML" to "Silverlight XAML" is done by the XpsToSilverlightXamlReader class, a minimal derivation from XmlReader that performs on-the-fly modification of the "XPS XAML" to translate it into "Silverlight XAML". Specifically, some elements are renamed, some attribute values are tweaked, and some attributes are removed entirely. The tweaking is done to address the Glyphs.FontUri/ImageBrush.ImageSource issue mentioned next and re-points the relevant content to an external location.
• XPS documents are entirely self-contained, with any necessary fonts and images embedded in the file (package) itself. This is great for simplifying distribution and Silverlight's Downloader class makes it easy to get at individual files in a package. However, SimpleSilverlightXpsViewer works best when the images and the fonts are extracted from the XPS file:
  • Under the right conditions, embedded images can be fetched by Silverlight by using the ImageBrush.SetSource method. However, things tend to break if there are multiple references to the same image in a single page (an exception is thrown when the second call to SetSource is made), so SimpleSilverlightXpsViewer doesn't enable this by default. Interested parties can #define SETSOURCE (for both C# files) to experiment with this feature (things work fine for the first page of all of the sample documents, but break on the second pages of the Blog and Site documents).
  • The default behavior of Glyphs.FontUri does not seem to automatically pull the font out of the package - at least not as it's used by SimpleSilverlightXpsViewer (possibly because Silverlight doesn't seem to like the leading '/' on package-relative paths). TextBlock has a SetFontSource method that seems interesting, but XPS XAML uses the Glyphs class which doesn't seem to support SetFontSource.
• For some reason, the XPS documents generated by the XPS printer driver aren't directly open-able by Silverlight's Downloader (a COM exception is thrown). However, I've found that a quick un-ZIP/re-ZIP with either of my favorite ZIP tools yields XPS documents that open right up. I suspect this is due to a simple issue with the Alpha Downloader implementation (endian-ness of the ZIP file, some special section embedded by the XPS printer driver, etc.) that could be fixed by the Silverlight team without much difficulty.
• Silverlight doesn't support the TIFF file format (which is not surprising because full support can be quite complex and TIFF images are hardly ever used on the web). As it happens, XPS printer driver output may contain TIFF images (it seems they're used as a mask of some kind behind another PNG or JPG image) - SimpleSilverlightXpsViewer simply ignores the TIFF images and neatly side-steps the support issue. :)

While SimpleSilverlightXpsViewer is a cute proof-of-concept application I enjoyed writing, it is hardly the final word on Silverlight XPS support. (Hey, I'm not even on the Silverlight team!) I don't know what the official plans are for more formal XPS support in the Silverlight platform, but my experience with SimpleSilverlightXpsViewer suggests that most of the pieces are already in place for a pretty reasonable XPS experience with the Silverlight 1.1 Alpha. Throw in a couple of tweaks to Silverlight (and/or SimpleSilverlightXpsViewer!), and it should be possible to provide a pretty compelling XPS-like user experience for Silverlight!

During his keynote at the MIX07 conference in Las Vegas, Scott Guthrie showed off some of the power of Microsoft's recently announced Silverlight platform. In particular, the ability to easily run managed code in the web browser - coupled with a powerful rendering engine - seems like it will to radically change the landscape of the web. My team had the privilege of writing the Silverlight Airlines demonstration he used to show off just how easy it is to develop with Silverlight. Demoed on stage, it looked something like the following image:

Now that your appetite is whetted, go ahead and click here (or on the image above) to view the demo in your browser with the Silverlight 1.1 Alpha thanks to the seamless cross-browser, cross-platform support that Silverlight provides.

When our manager Shawn Burke asked us to put this demo together, my coworker Ted Glaza and I had practically no experience with Silverlight or WPF. So we spent about a week playing around with the technology to learn how it worked. By that time, the general concept of the demo was fairly well established and we spent time the next week developing the foundations of the application. Before long, we had a working demo that we showed off to Scott. The third week was spent incorporating visual feedback from a designer and adding some finishing touches. For those of you keeping track at home, that's one cool app written by two developers in just three weeks - beginning with nothing and building on top of a platform that was still being developed - pretty compelling, I think!

In the spirit of openness and learning, you can click here to download the complete source code for this demo application and play around with it yourself!

A few notes on the application:

• It's implemented as three self-contained controls (the map, calendar, and itinerary picker) that are hooked together via a couple of simple event handlers and property accessors.
• The goal of code/design separation was achieved here to an extent I haven't experienced before. In particular, the fact that we were able to incorporate an external party's XAML design into our existing code with such ease was a rare treat.
• I experimented with a vaguely CSS-y approach to XAML design with the calendar and itinerary picker controls I wrote, overlapping a number of different styles and using opacity to display the right style at the right time. I liked the way it worked out here because it enabled me to (for example) completely define the look of the calendar's day cells in a single XAML file - even though that style is actually somewhat complex (there are different styles for alternating months, weekends, hovering, selection, etc.).
• The "plane flying" animation was Ted's doing and adds a really nice effect. All it took to implement was a plane graphic, a few transforms, a couple of animations, and a bit of high school math. :)
• The XAML content is automatically resized to fit the browser window (while maintaining its original aspect ratio) with some JavaScript code that hooks the Silverlight control's onLoad and onResize events and manipulates two simple transforms it creates for that purpose. Silverlight lets you program against it with C# and JavaScript - at the same time!
• In order to compile and build the source code, you need Visual Studio "Orcas" Beta 1 and the Silverlight Tools installed on you machine. Complete details and download links for these tools (and others) can be found on the Silverlight web site.
• The inspiration for the demo application came from Bret Victor's Magic Ink essay which is a great read and recommended for anyone who's interested in user interface design.

The Silverlight Airlines demo was a fun project to work on - I look forward to be seeing (and doing!) a lot more with Silverlight in the coming days!

PS - Since the keynote presentation, there has been some interest in reusing the calendar control. Beyond making the source code available here, I may write a follow-up blog post going into more detail about the calendar itself. As a quick teaser: it's capable of more sophisticated display than what's in the demo application. :)

PPS - If you watched the Scott Guthrie keynote, you probably saw that there was a time Scott tried to switch the display screen over to the Mac to demonstrate something and it took a while for the conference's A/V folks to actually make the switch. A couple of people have asked if this delay was due to a problem with the Mac or Silverlight. I happen to have been sitting backstage mere inches away from the Mac in question (conferences use KVM switches to keep all the demo machines backstage) and I can assure you that there was no technical issue with the Mac or Silverlight. Aside from the conference tech taking a little while to switch the display over, there were no technical glitches during the demo. :)

We've just made available the AJAX Control Toolkit Patch Utility, a simple ClickOnce application that makes it easy for *anyone* to contribute fixes to the AJAX Control Toolkit!

Background: We have a very active user community that's using the Toolkit in lots of ways we never imagined. Sometimes people come up with better ways of doing things and occasionally they bump into a new issue we didn't know about. When questions show up on the support forum, it's great to see someone follow up with a change to the Toolkit that resolves the issue. These community contributions are fantastic - we always try to add a pointer to the associated work item for the issue so we won't forget about it. However, there is a fair amount of effort involved in merging such fixes into the Development branch of the source code and that effort can delay the incorporation of proposed changes. The new Patch Utility is designed to streamline the process so it will be easier for people to contribute fixes and easier for the Toolkit team to incorporate them into the next release of the Toolkit. By making the process simpler and enabling the inclusion of more community fixes, everyone benefits by having a better Toolkit that they're less likely to have trouble with!

How patching works: The AJAX Control Toolkit Patch Utility Guide contains all the details - along with screenshots that walk through everything. The process itself is pretty simple. Once a Toolkit user identifies a problem, he/she runs the Patch Utility in "Create a Patch" mode which walks through the steps of downloading the latest Development branch of source code for the Toolkit. The user makes whatever changes to the Toolkit are necessary to fix the problem and alters the automated test cases to verify the new behavior. Then the user runs the Patch Utility again in "Prepare Patch for Submission" mode which collects the changes that were made, gives the user an opportunity to review them in a file differencing tool, and generates a compact ZIP archive containing the user's patch. The user attaches the ZIP file to the existing work item that corresponds to the issue he/she fixed and that's it!

What happens next: On the back end, we have a process running which periodically looks at outstanding work items for new patches. When a new patch is found, a set of "check-in-able" changes is automatically created for that patch. What that means for the Toolkit team is that it's easy for any of us to review the patch, merge it with the very latest version of code in the Development branch, test it on our machines, and check the patch in for inclusion with the next Toolkit release!

What changes make good patches: Bug fixes and minor enhancements to existing code make great patches because the overall amount of change is small and the effect of the change is fairly self-contained and easily testable. On the other hand, broad changes like the addition of an entirely new control or the refactoring of a significant chunk of code would not make good patches due to the widespread effects of such changes (we have a different process in place for such things; email us if you want to add a new control).

The Patch Utility enables anyone to make fixes to the Toolkit - if you're a Toolkit user and you've got a fix floating around on your machine, please use the AJAX Control Toolkit Patch Utility to submit it! And if you have any suggestions for things we can improve please send your feedback to us!

By default, the AJAX Control Toolkit's AutoComplete extender doesn't have a notion of "words" and will try to auto-complete whatever text is currently in the text box, treating what's there as a single "word". One request that has come up a few times was for the ability to auto-complete multiple words individually. According to the comments of that work item, it looks like someone's made a set of proposed changes to do just that! It's great to have such an involved user community!! (Please note: The work item comments suggest those changes don't work in all browsers.)

One thing I'd been meaning to do was write a quick sample of how to get reasonably good multiple-word auto-complete without making any modifications to the released AutoComplete extender. In other words, you can use the latest official Toolkit release (10301 in this case) and get some nice multi-word completion today. The key observation here is that the Web Service used to provide the list of candidate words has all the information it needs to do multi-word completion as well:

The complete code for the sample page is included below for anyone to look at or modify for their purposes. A few notes about the code:

• The example was written to be simple, not efficient. The goal is to demonstrate the idea as plainly as possible, so there's no focus on performance.
• The code works by auto-completing the last "word" of input and then populates the list of candidates with the resulting words and the preceding text.
• All comparisons are case-insensitive so the user can type however they want.
• In a real-world application, the list of candidate words would probably be retrieved from a helper function, a database, etc..

Here's the complete ASPX file:

Enjoy!