Jim O'Neil's Blog : Dynamic Data

ASP.NET Dynamic Data Preview 4 Available

joneil — Thu, 07 May 2009 17:37:06 GMT

The latest preview release of ASP.NET Dynamic Data is now available from CodePlex. These previews give you insight into the feature set that will be available when .NET 4 is released; however, you can start using them right now with .NET 3.5 SP1!

I’ve done quite a few presentations on Dynamic Data (check out my screen cast for a taste of what it can do), so I’m looking forward to playing with the new bits. This drop is specifically focused on integrating the coolness of field templates and validation into your existing sites, which is really where the true potential of Dynamic Data lies.

Here’s a blurb from Scott Hunter’s blog post:

When we look back and see how people view Dynamic Data we regret that people immediately think of it as scaffolding of data. This is something that it does do, and I think it does a pretty good job at it. But Dynamic Data is a lot more then that, providing a new templating mechanism called Field Templates which allow the default markup for many of our built in data controls to be more easily customized. These field templates also support validation by default (something our rich data controls did not) which can be customized by adding metadata to data objects.

In the past to enable Dynamic Data functionality in a web application the application needed to follow a couple of rules:

- It had to have a data model such as Entity Framework or Linq to SQL

- The data model had to be registered at startup in Global.asax

- The DynamicData directory had to exist in the web application

One of the new features this new preview release supports is adding field templates and validation to any ASP.NET web page without having to meet these requirements.

Dynamic Data Resources

joneil — Thu, 16 Apr 2009 06:35:40 GMT

Thanks to all that turned out at the ASP.NET Professionals User Group tonight in Waltham to hear about ASP.NET Dynamic Data. As promised, I’m listing the resources I provided on my closing slide here, and I’ll provide a few pointers to answer some of the questions in a little more detail as well.

Resources

http://asp.net/dynamicdata – main site, including “How Do I” videos

ASP.NET Dynamic Data 4.0 Preview 3

vNext sample – incorporates functionality targeted for the Dynamic Data 4.0 release (coinciding with .NET 4.0), but compiled with 3.5 SP1 bits, so you can experiment with the functionality now

Futures project – additional functionality to extend the current release including support for advanced filtering and the application of metadata at runtime

Design for Data – Dan Crowell’s community repository of CSS styles for Dynamic Data

Blogs

Scott Hunter – Dynamic Data Program Manager

David Ebbo – Dynamic Data architect

Stephen Naughton – UK developer focusing on Dynamic Data

Screencast and slides/demo from a previous version of the presentation I gave tonight

Questions

Q. How can I control what properties/columns appear in display mode versus edit mode? For instance, we added a composite ‘fullname’ property for the List view, but we needed the individual first name and last name field on the edit view.

A. To handle this you’ll have to do a little bit of coding; Stephen Naughton’s blog post will lead you through this. The gist of the solution is that you create a new attribute to specify the conditions under which the affected properties/columns should be displayed. Secondly, you implement your own customized field generator (interface IAutoFieldGenerator) to examine the attribute and either include or exclude the property/column from the GridView, DetailsView, ListView, etc.

Q. Can I use mechanisms other than ASP.NET membership to specify roles and permissions for accessing or updating specific properties in the model?

A. You can pretty much do whatever you want using a combination of custom attributes and injecting a bit of code at appropriate access points. Stephen has a great series of posts that provides a lot of detail in setting up an access scheme, one that could leverage the existing ASP.NET membership infrastructure or a mechanism of your own choosing.

Q. Are there any books on ASP.NET Dynamic Data?

A. The only one I found was a Wrox Blox PDF, a 34-page downloadable e-book. I also have the following ASP.NET 3.5 books on hand,

Professional ASP.NET 3.5 in C# and VB

Programming Microsoft ASP.NET 3.5

Learning ASP.NET 3.5 (Second Edition)

but only the latter even mentions Dynamic Data, and doesn’t do much more than describe the feature. Granted, Dynamic Data was part of the 3.5 Service Pack 1 release, so many of these books may have already been in the publication phase before the feature was nailed down. There is also Programming ASP.NET 3.5, but I don’t have that one handy, so not sure what coverage there is of Dynamic Data.

Hmm, perhaps it’s an opportunity for you to be the next great American author!

Dynamic Data @ ASP.NET Professionals User Group

joneil — Mon, 13 Apr 2009 16:07:00 GMT

I’ll be presenting at the second meeting of the ASP.NET Professionals User Group this coming Wednesday in Waltham. Fritz Onion kicked things off last month with “The Changing Face of ASP.NET,” an overview of what developers need to know before embarking on their next ASP.NET project. This month we’ll take a deeper dive into one of the technologies Fritz touched on, namely ASP.NET Dynamic Data:

Dynamic Data: From Data to CRUD in Five Minutes (or so)

ASP.NET Dynamic Data, introduced with the .NET Framework 3.5 SP1, is a customizable, scaffolding framework for building data-driven ASP.NET web sites. Layering on top of data access technologies like LINQ to SQL and Entity Framework, you can build a CRUD (Create-Read-Update-Delete) site literally in minutes. Additionally, you can make use of new dynamic controls, page and control templates, and custom validation to extend your site far beyond the 'out-of-the-box' experience.

Date	Wednesday, April 15, 2009
Time	6:15 – 8:30 p.m (save doing your taxes for after the meeting!)
Place	Microsoft 201 Jones Road Waltham MA 02451

TONIGHT! Inaugural Meeting of ASP.NET Professionals

joneil — Mon, 16 Mar 2009 16:30:00 GMT

Quick reminder: the first meeting of the newly formed ASP.NET Professionals User Group takes place tonight at the Microsoft office at 201 Jones Road in Waltham. The meeting runs from 6:15 to 8:30. Regular meetings will occur on the 4th Tuesday of each month.

Kicking off the new group tonight will be Fritz Onion speaking on

The Changing Face of ASP.NET Development

Ajax, MVC, jQuery, DynamicData - things you should know before you start your next ASP.NET project.

.NET Framework 3.5 SP1 Update Released

joneil — Sun, 04 Jan 2009 08:09:42 GMT

This is sort of 'last year's news' since the KB article for the update has a date of December 31st, but I suspect many of you weren't all that tuned in to patch releases over the holidays!

The update resolves a number of issues, including some related to topics I've recently presented:

ASP.NET Dynamic Data: In the 3.5 SP1 release, 1-to-1 relationships among entities in the Entity Framework were not supported. There was a workaround posted for this which is now superseded by the SP1 update.

ADO.NET Data Services: Since the ADO.NET Data Services Client did not support creating an entity and setting a reference association (e.g., a foreign key column) in the same step, you could not create new entities if the underlying database schema represented that relationship as a non-nullable foreign key.

Some Upcoming Events

joneil — Fri, 31 Oct 2008 18:51:30 GMT

I'll be out and about in New England during the first two weeks of November, so just wanted to let you all know of a few events

Nov 4th, 5 - 8 p.m.	Rhode Island .NET User Group Roger Williams University Bristol, Rhode Island Topic: ASP.NET Dynamic Data
Nov 5th, 1 - 5 p.m.	MSDN Event (click to register) Courtyard by Mariott 63 Grand Street Waterbury, Connecticut
Nov 13th, 1 - 5 p.m.	MSDN Event (click to register) Sheraton Boston 39 Dalton Street Boston, Massachusetts

Dynamic Data VB Style

joneil — Fri, 05 Sep 2008 08:21:23 GMT

Thanks to the New England Visual Basic Professionals User Group for the invitation to speak on ASP.NET Dynamic Data this evening in Waltham. AV glitches and the mass migration from MPR-C to MPR-B aside, I hope the content was relevant and useful. This was my first time presenting a VB version of this talk, and I have to comment that it was also the most interactive group I've spoken to on the subject! As a result, while we got through the nuts and bolts, we didn't get to discuss other concerns about deploying Dynamic Data sites like adding business validation rules, addressing security, etc.

To that end, I'm posting the presentation slides on my SkyDrive, as well as the VB version of the ASP.NET Routing Demo that we looked at. As always, I'm available via e-mail or through the blog feedback channel if you have any question or comments on these material (or actually on anything in general related to developing on the Microsoft platform).

I'm also listing the resource links that I showed at the end of the presentation here for future reference:

ASP.NET Dynamic Data Web Site: http://www.asp.net/dynamicdata

Microsoft Blogs

Scott Hunter - http://blogs.msdn.com/scothu
David Ebbo – http://blogs.msdn.com/davidebb
Marcin Dobosz – http://blogs.msdn.com/marcinon

External Blogs

Steven Naughton - http://csharpbits.notaclue.net/
Matt Berseth - http://mattberseth.com
Josh Heyse - http://blogs.catalystss.com/blogs/josh_heyse

Dynamic Data in Waltham

joneil — Sun, 31 Aug 2008 06:21:49 GMT

This coming Thursday, September 4th, I'll be presenting on ASP.NET Dynamic Data to the New England Visual Basic Professional User Group at Microsoft's Waltham office, 201 Jones Road (one-click directions). I started working with this technology at the beginning of the summer, and now that's its been officially released as part of .NET 3.5 SP1, there's definitely been some momentum and new folks blogging about and extending the technology. If you haven't looked at it yet, this is a great way to get an introduction and hit the ground running! Hope to see you there.

Caching in ASP.NET Dynamic Data

joneil — Sat, 26 Jul 2008 05:12:19 GMT

One question that came up at my presentation to the Maine Bytes user group this week centered around the degree to which Dynamic Data will leverage ASP.NET caching. Given that the UI of a Dynamic Data site more or less comprises a small set of page and control templates, and it's often just the data that changes as you navigate, it would seem to be a great opportunity to cache the presentation markup. On the other hand, the on-the-fly nature of the page generation led me to suspect that there may not be much opportunity after all. At the time I didn't have as definitive an answer as I'd like... so I went to the source of all that is right and good -- engineering!

As explained to me, since the default templates are all wrapped in an AJAX UpdatePanel, the pages are pretty much going be re-rendered on every postback. If you use a tool like Fiddler, you can see empirically that this indeed is the case. Now some of the ways to avoid this is to move to more of an AJAX approach where client-processing can be leveraged more effectively, and that's a direction that the Dynamic Data team may look at as the feature matures. In the meantime, since it's ultimately just ASP.NET Web Forms under the covers, caching techniques and strategies that are appropriate for traditional, non-Dynamic Data ASP.NET sites would still be applicable here.

Now another aspect of caching is that of the data model and its attributes. The model *is* cached when registered via the MetaModel.RegisterContext method in the Application_Start event. That's great in terms of performance, given how frequently the model is consulted as the site pages are generated; however, a drawback (perhaps affecting just more advanced scenarios) is that you can't modify the model dynamically (such as by using a custom metadata provider) because the cache is not refreshed once initialized. Check out Marcin's post on that topic.

Dynamic Data Just Got Cooler

joneil — Sat, 26 Jul 2008 04:13:09 GMT

Scott Hunter, the Program Manager for ASP.NET Dynamic Data, announced the Dynamic Data for MVC Preview available on CodePlex. This takes the powerful scaffolding and data validation models that we see applied to Web Form applications in .NET 3.5 SP1 to the MVC framework. Note it's a very early preview so is not as functional as the Web Forms version is today, but it's an exciting step nonetheless.

Dynamic Data References

joneil — Sun, 20 Jul 2008 00:25:29 GMT

Thanks to David Hockenberry, Mike Pawelek, and the Western New York .NET Users Group for hosting me last Wednesday. I had a great time meeting many of you while presenting on the new ASP.NET Dynamic Data feature in .NET 3.5 SP1. As promised, I wanted to provide some of the references I mentioned during the talk; I'll be uploading the presentation to my SkyDrive within the next week or so.

The go-to reference is the ASP.NET site: http://www.asp.net/dynamicdata
You definitely want to use the latest bits of Dynamic Data versus what was part of the beta. Note, these were released *yesterday*, so I've got some catching up to do myself!
I recommend downloading the documentation for the latest bits; however, if you are content with the original SP1 beta download, you can access the MSDN documentation on-line as well.
Bloggers: Scott Hunter (Program Manager), Marcin Dobosz (development), David Ebbo (development), Stephen Naughton (community)

Look for another exciting announcement regarding ASP.NET Dynamic Data early next week.

Buffalo Bound

joneil — Sat, 12 Jul 2008 05:57:03 GMT

I'm heading to Buffalo, New York, next Wednesday (July 16th) for the Western New York .NET User Group meeting. The topic is ASP.NET Dynamic Data, a really RAD (and rad!) addition to the upcoming .NET 3.5 SP1 release.

	Date:	July 16, 2008
	Time:	6 - 8:30 p.m.
	Location:	KnowledgeAir Larkin Building, Suite 628, 726 Exchange Street
	Food:	Pizza and pop (Courtesy of Technisource)

Be sure to RSVP so the folks there have an accurate count for the munchies

Constraints in ASP.NET Routing

joneil — Tue, 08 Jul 2008 00:36:21 GMT

ASP.NET routing is a new feature incorporated in the upcoming .NET 3.5 Service Pack 1 release. While closely associated with the implementation of ASP.NET MVC (Model-View-Controller), it's really a separate piece of functionality consolidated in two assemblies

System.Web.Routing, and
System.Web.Abstractions

I've been looking at routing recently as part of ASP.NET Dynamic Data, and soon found myself intrigued by the various permutations you can cook up. While there are quite a few blog posts and tutorials on the routing feature, I haven't found many (yet) that talk much about the new constraint capabilities introduced in ASP.NET MVC Preview 3.

In a nutshell, ASP.NET routing allows you to set up a RouteTable consisting of URL 'templates' against which the System.Web.UrlRoutingModule (referenced in web.config) compares each requested URL to see if there is a match. If there is, the HTTP request is handed off to a specific implementation of an IHttpHandler for servicing. ASP.NET MVC comes with its own implementation of an IHttpHandler (System.Web.Mvc.MvcRouteHandler), but where's the fun in that... so that's when I decided to try my own hand.

As I mentioned, each route is really a template. For instance, a URL of

dayinhistory/{year}/{month}/{day}

would match things like

http://mysite.com/dayinhistory/2000/1/1

and assign values to "year", "month", and "day" in a Values collection that can be accessed within the route handler. Unfortunately, it would also match URLs like

http://mysite.com/dayinhistory/red/sox/rock

http://mysite.com/dayinhistory/2000/56/40

neither of which represents a valid date.

While each route definition can be initialized with a collection of Constraints, prior to ASP.NET MVC Preview 3, the constraint itself could only be a string representing a regular expression. That works for some scenarios, but it doesn't really help when you have more complex validation, such as date checking.

With Preview 3, a new interface, IRouteConstraint, was added to System.Web.Routing and vastly expands your constraint-checking capabilities. Now you can specify a constraint not only as string (to be interpreted as a regular expression, as in the past) but also as a custom class implementing this new interface. IRouteConstraint mandates implementation of a Match method, within which you can do pretty much anything and then simply return true if the validation succeeds or false if it fails.

As you can see from the Match signature below, you have access to the selected route, the substituted URL parameters, and the HTTP context object to perform the validation. The routeDirection parameter is an enumeration that tells you whether the method is executing on an 'incoming' basis, that is the UrlRoutingModule is trying to find a match for a requested URL, or on an 'outgoing' basis, in which you're requesting a URL to be created to match a route - generally in response to invoking GetVirtualPath to build URLs for links within your own pages.

public bool Match(HttpContextBase httpContext, Route route, 
     string parameterName, RouteValueDictionary values, RouteDirection routeDirection)

As an example, here's a simple class I created to validate the date URL pattern mentioned above. It simply tries to create a date from the parameter values extracted from the URL, and if that fails (i.e., an exception is thrown), the validation fails.

public class DateConstraintValidator : IRouteConstraint
{
    public bool Match(HttpContextBase httpContext, Route route, string parameterName, 
                      RouteValueDictionary values, RouteDirection routeDirection)
    {
        try
        {
            DateTime potentialDate = new DateTime(
                Int32.Parse(values["year"].ToString()), 
                Int32.Parse(values["month"].ToString()), 
                Int32.Parse(values["day"].ToString()));
            return true;
        }
        catch (Exception)
        {
            return false;
        }
    }
}

Now, my route definition in global.asax looks like this (DateUrlRouter is my custom IHttpHandler that instantiates a single ASPX page to display the date in a Calendar control):

Route r = new Route("dayinhistory/{year}/{month}/{day}", 
    null,                
    new RouteValueDictionary { {"year", new DateConstraintValidator()} }, 
    new DateUrlRouter());
routes.Add(r);

While I only have one constraint on "year", that's really enough, because the Match method has access to all of the substituted values as one of its parameters. (Actually, it doesn't really matter what value is supplied for the string "year" here, since the constraint reference will come along for the ride anyway!)

If you're interested in seeing this all in action, check out my sample on Skydrive: