I presented a talk called "Enterprise Data Validation" at the Hampton Road .NET User Group this evening. The premise was simple. Data validation needs to happen in all the tiers of a modern application but the validation rules should be defined only once to avoid synchronization errors. In this talk, I showed how to extend SQL Server using extended properties to store regular expressions for data validation as column metadata. I also showed how to add a regular expression matcher to SQL Server using the SQL CLR and how to add check constraints to invoke the regular expression parser. Then I built a WCF service to query the validation metadata to make it available in other application tiers. I quickly assembled WCF service host and client showed how you could bring all of the elements together to create a working Enterprise Validation solution.

Download the SQL Scripts (20.06 kb)

I spoke at the Charlottesville .NET User Group this week and at the Raleigh Code Camp. I cheated and did the same presentation to both groups. Call me lazy but, in the middle of planning our own Code Camp in Richmond, I really didn't want to prepare two separate talks. I did a talk back at CodeStock 2009 on a similar topic back in June 2009 but it's evolved a lot since then based on my own growth and understanding. You can find the code and slides below.

UPDATED on 30 June 2009

I spoke at the CodeStock 2009 conference and I thought it would be helpful for the attendees and others to be able to download my code and slides. The title of my presentation was "How I Learned to Love Metaprogramming" and it concerns Dynamic Language Runtime architecture, performance of dynamic typing and Python to C# integration. The slides and source code are linked below. I will be giving this talk again in September at the Charlottesville .NET User Group meeting. Both of the demos require C# 4.0 which is available in Visual Studio 2010.

• Demo One - shows how to do XML parsing using a fluent interface based on a DynamicObject derivation in C# 4.0
• Demo Two - shows how the Level 0, 1 and 2 CallSite and ActionBinder caches perform. UPDATED: I added a demo on 30 June 2009 that shows how the DLR 0.9 compares by invoking dynamic code through the DLR hosting APIs, thereby bypassing the CallSite caching mechanisms. The results are very instructive, showing that the DLR's polymorphic inline caching can yield a 250000% increase in performance. You read that correctly: a two hundrend fifty thousand percent increase in performance.

Slides in PDF (Acrobat) format (688.49 kb) 
Slides in PPTX (PowerPoint 2007) format (639.23 kb) 
Demo One Source Code - MetaObjectPlay200905.zip (5.17 kb) 
Demo Two Source Code - PythonIntegration200906.zip (5.33 kb)

In part 1 of this article, I showed you how to create a fluent parser for XML documents as a dynamic type in C# 4. With that dynamic class, you can use the dot (.) and index ([]) operators to traverse any XML document with a very natural syntax. Being able to read XML fluently is great. But to be really useful, our dynamic class should allow the programmer to modify the XML document fluently as well. To do this, we'll need to modify the behavior of the overridden TryGetMember method to create missing XElements whenever they are referenced by the code. Here's the modified code for the TryGetMember method:

Parsing XML documents using a fluent interface is a very compelling idea. Given some simple XML that contains information about books and their authors (see the end of this article for a sample), I'd like to be able to parse it with something like this:

Parsing XML documents using a fluent interface is a very compelling idea. Given some simple XML that contains information about books and their authors (see the end of this article for a sample), I'd like to be able to parse it with something like this:

// for brevity, not all of the XML is shown here - use your imagination
string xml = "<books><book><authors>...<authors></book>...</books>";

// create a dynamic XML parser that enables a fluent interface
dynamic dx = new DynamicXml( xml );

// show the last name of the 1st author of the 3rd book
Console.WriteLine( dx.book[2].authors.author[0].name.last );

Welcome to Part 4 of a multi-part series on JavaScript Object Notation (JSON) support in the Microsoft .NET Framework. In this article, we'll focus on the JavaScriptConverter class from the System.Web.Script.Serialization namespace. You can find the other parts of this series at these locations:

Welcome to Part 4 of a multi-part series on JavaScript Object Notation (JSON) support in the Microsoft .NET Framework. In this article, we'll focus on the JavaScriptConverter class from the System.Web.Script.Serialization namespace. You can find the other parts of this series at these locations:

Welcome to Part 3 of a multi-part series on JavaScript Object Notation (JSON) support in the Microsoft .NET Framework. In this article, we'll focus on performing JSON serialization from a RESTful WCF web service. You can find the other parts of this series at these locations:

Welcome to Part 3 of a multi-part series on JavaScript Object Notation (JSON) support in the Microsoft .NET Framework. In this article, we'll focus on performing JSON serialization from a RESTful WCF web service. You can find the other parts of this series at these locations: