Silverlight 3 RTW正式版发布附Silverlight 3开发工具下载地址

Silverlight 3 Release Date (RTW) Surprise

Update 07/08/2009: Silverlight 3 RTW has been released. Please visit my blog post here for all the download links:

http://silverlighthack.com/post/2009/07/09/Silverlight-3-Relase-and-Download-Links.aspx

Update 05/28/2009: Scott Guthrie during his online talk yesterday mentioned that Silverlight 3 is close to being finished up and will be released "soon". I remember when he mentioned that during Silverlight 2 Beta 2/RC0 and Silverlight 2 RTW was out within a few weeks. The release is REAL close now! Expression Blend 3 is also getting some updates in RTW. Also note the July 10, 2009 invitation to talk about Silverlight 3...http://arstechnica.com/microsoft/news/2009/05/silverlight-3-and-expression-studio-3-launching-july-10.ars

Silverlight 3 Beta 1 was released last week during the MIX 2009 conference. This version of Silverlight includes many enhancements that many developers want to incorporate into their RIA projects now. The first question that comes to mind to many architectes or development decision makers is, when is the framework going to be released so they can plan their product development schedule. Unfrotunately, during the conference, Microsoft did not provide clear guidance on when to expect Silverlight 3 RTW. This article tries to gauge when Silverlight 3 will be released and why.

Based on the public knowledge available Microsoft released a few days ago, we can deduce when Silverlight 3 will be released. What does it mean when we talk about the "Silverlight 3 release date"?

"Silverlight 3 is now much more than just

simply installing the SDK and the runtime."

At its core, the "Silverlight 3 release" includes several key dependent tools and technologies that need to be released together:

• Silverlight 3 SDK
• Silverlight 3 Tools for Visual Studio (2008/2010)
• Expression Blend 3
• .NET RIA Services
• Silverlight 3 Control Toolkit (not directly part of SL 3, but release schedule has been matching Silverlight schedule)

As you can see, this list has grown from when Silverlight 1.0 or 2.0 was released. When Silverlight 1.0 was released, only Blend, the SDK and the tools were released. Furthermore, the list of tools will no doubt grow when mobile support is added to the Silverlight runtime. With all of these dependencies, it obviously will take longer for a Silverlight release and that has to be considered when predicting when the release will happen.

Past Silverlight Release Cycles

Let's take a look at the past release cycles of Silverlight 1.0 and Silverlight 2.0 of the major betas and releases:

Silverlight 1.0 (about 2 years between first public alpha/beta -> RTM/RTW)

• WPF /E (several betas internal and external in 2006)
• Silverlight 1.0 Beta (March 2007)
• Silverlight 1.0 RC1 (July 2007)
• Silverlight 1.0 RTW (September 2007)

Silverlight 2.0 (about 1.5 years between first public alpha/beta -> RTM/RTW)

• Silverlight 1.1 Alpha (March 2007)
• Silverlight 2.0 Beta 1 (March 2008)
• Silverlight 2.0 Beta 2 (June 2008)
• Silverlight 2.0 RC1 (October 2008)
• Silverlight 2.0 RTW (October 2008)

As you can see, both Silverlight 1 and Silverlight 2 have had pretty long development cycles between public betas to when they were finally released. If I were a betting man based on the past information, I would bet that Silverlight 3 RTW would be a long way away (at least 5-6 months away). Furthermore, Silverlight 1.0 has had three "beta" releases and Silverlight 2 had four "beta" releases. I even posted my thoughts on this in the Silverlight forums, based on my assumption that Silverlight 3 would be out around when VS 2010 is released later this year.

Silverlight 3 Release Date Hints

After watching some more of the videos from MIX 2009, more information has come out to make my assumption of a release in the 6-9 month timeframe incorrect.

PowerPoint Slide from MIX 2009 - Deep Dive into Microsoft Silverlight Graphics

From the slide above, we can see that Microsoft is actually planning a release in the Summer of 2009! That would mean it would be about a 3-6 month release cycle from the first beta to RTW. This is pretty surprising when comparing it to the Silverlight 1 and Silverlight 2 release cycles which were over 18 months. This information was reiterated in a Scott Guthrie interview recently that only one beta of Silverlight 3 was planned.

Possible reasons for a shorter release cycle

Based on the information above, we can safely assume that Microsoft is going to deliver Silverlight 3 in one of the quickest release cycles for Silverlight. How is Microsoft accomplishing this? I can only speculate (based on public information), but I think it has to do with a few key reasons:

• Silverlight 3 is like .NET 3.0 as Silverlight 2 is to .NET 2.0. .NET 3.0 added WCF, WPF, WF and Cardspace to .NET 2.0; however, the core framework did not change. Silverlight 2 uses .NET 3.5/Visual Studio 2008 and Silverlight 3 does the same. I think that Silverlight 3 essentially builds upon the CLR with additional assemblies and doesn't change the core of Silverlight 2 much (I could be dead wrong here).
• Silverlight Mobile is conspicuously missing from Silverlight 3. Silverlight Mobile was demo'ed way back in April 2007. Microsoft showed off Silverlight 2 on mobile devices in October 2008. Silverlight 3 obviously does not include any mobile support. I think Microsoft cut this feature out as they re-thought their mobile strategy focusing it towards Windows 7 Mobile (out in 2010). Cutting this major feature out allowed Microsoft to push up the date by several months.
• Silverlight 3 is essentially going to have tool support both in Visual Studio 2008 and Visual Studio 2010. Visual Studio 2010 will add a rich designer for Silverlight 3 where developers will be able to interact with the XAML/designer much like they are able to now with Blend. However, this support is NOT being added into Visual Studio 2008 (even though in Scott Guthrie's Silverlight 3 glimpse in November 2008 it looked like it would be added to VS2008). So what? I think that the Silverlight 3 could come in parts and all of the tools won't be released until the end of 2009. We got another hint of that with Expression Blend 3 Beta not having all of the features being present (i.e., Sketchflow). For example, .NET RIA Services might not be released RTW with Silverlight 3 in the Summer of 2009.
• Silverlight 3 is a key part to Microsoft's UI strategy and it really catches up to a majority of Adobe's Flash/Flex features. Silverlight still has some features missing that Flash/Flex technology has (i.e., printing, microphone, web cam.) However, Silverlight 3 adds and builds upon several key features that Flash/Flex simply still don't have on their radar (line of business framework, enterprise integration, multithreading). The Silverlight 3 feature set will roughly equate to the Flash/Flex feature set.

What about Visual Studio 2010

Update note: Visual Studio 2010 Beta 1 public release is "in a matter of months now" according to Mark Wilson (http://videos.visitmix.com/MIX09/T73M). Maybe VS 2010 Beta 1 will be released when Silverlight 3 RTW is released in the summer? Remember Silverlight 3 is NOT dependent on VS 2010 and will work in VS 2008 and VS 2010. Microsoft very well might release Silverlight 3 in the summer. VS 2010 support and add-ons such as .NET RIA Services might come later.

In conculsion, it is a pleasant surprise that Microsoft is planning on releasing Silverlight 3 in the Summer of 2009. This would make Silverlight 3 have the shortest release cycle out of all of the previous Silverlight releases. This release packs a lot of features and has excellent tool additions which can benefit many RIA developers. However, I think that Microsoft may have dropped certain features (i.e., mobile support) from the release. Furthermore, the full Silverlight 3 developer experience may not be fully realized until Visual Studio 2010 is released. This might hurt the release in the long run. Personally, I am excited about the early Silverlight 3 release date. The early date allows me to start architecting on the new framework with confidence that my application will not be waiting for months on Microsoft for Silverlight 3 RTW.