DotNetKicks.com : Stories kicked by paul_houle

Stop Catching Exceptions!

Tue, 05 Aug 2008 13:35:12 GMT

Too many programmers catch exceptions too often, causing both mainline and error handling logic to be complex and error-prone. Although C#, PHP and other languages don't make the mistake that Java made with Checked Exceptions, Java trained a generation of programmers in bad habits. A strategy that (i) uses finally as the first resort for containing corrupting and maintaining invariants, (ii) uses catch locally when the exceptions thrown in an area are completely understood, and (iii) surrounds independent units of work with try-catch blocks is an effective basis for using exceptions that can be built upon to develop an exception handling policy for a particular application.

The Mysterious Multiton Manages Asynchronous State Updates

Fri, 25 Jul 2008 16:14:55 GMT

The Muliton Pattern is an initialization pattern in the sense defined in the notorious "Design Patterns" Book. Mulitons are like Singletons in that they use static methods to control access to a private constructor, but instead of maintaining a single copy of an object in an address space, a Multiton maintains a mapping from key values to objects. A number of uses are emerging for mulitons: (i) Multitons are useful when we want to use something like the Singleton pattern, but support multiple named instances of a system in an an address space and (ii) Multitons can be a useful representation of an object in a persistent store, such as a relational database.

Building Reliable Silverlight Apps With Model-View Separation

Mon, 21 Jul 2008 15:17:19 GMT

When people start developing RIA's in environments such as Silverlight they often write asynchronous communication callbacks in an unstructured manner, putting them wherever is convenient - often in a instance members of user interface components. Several problems almost invariably occur as applications become more complex that force the development of an architecture that decouples communication event handlers from the user interface: a straightforward answer is to create a model layer that's responsible for notifying interested user interface components about data updates.

Missing Keys in Dictionaries: Semantics of C#, Java, PHP and Python

Thu, 17 Jul 2008 16:45:12 GMT

Today's popular languages implement Dictionaries: a structure that can efficiently look up values associated with a set of keys. On close examination, we find that different implementations provide programmers different options for missing keys: something that can make a big difference for the reliability and maintainability of applications. This article contrasts the implementation of Dictionaries in C#, PHP, Python and Java and provides implementations of Python-style semantics as a PHP function and C# extension method

The Weird And Wonderful World Of Extension Methods in C#

Wed, 09 Jul 2008 11:46:18 GMT

Extension methods are the most controversial feature that Microsoft has introduced in C# 3.0. Introduced to support the LINQ query framework, extension methods make it possible to define new methods for existing classes. Although extension methods can greatly simplify code that uses them, many are concerned that they could transform C# into something that programmers find unrecognizable, or that C#'s namespace mechanisms are inadequate for managing large systems that use extension methods. Adoption of the LINQ framework, however, means that extension methods are here to stay, and that .net programmers need to understand how to use them effectively, and, in particular, how extension methods are different from regular methods.

Dropping Unique Constraints in SQL Server

Mon, 30 Jun 2008 13:42:35 GMT

This article presents a simple stored procedure which makes it possible to delete a stored procedure in SQL Server without knowing it's name, an important tool when automating the maintainance of database schemas in Microsoft SQL Server

How To Access The User Interface Thread In Silverlight 2

Wed, 25 Jun 2008 21:02:17 GMT

Silverlight 2 Beta 2 introduces a major change in the concurrency model for asynchronous communication requests. Unlike SL2B1, where asynchronous requests executed on the user interface thread, SL2B2 launches asynchronous callbacks on multiple threads. Although this model offers better performance and responsiveness, it requires Silverlight programmers to explicitly transfer execution to the UI thread before accessing UI objects: most SL2B1 applications will need to be reworked. This article introduces a simple static class, UIThread, which makes it easy to schedule execution in the UI Thread.

Which kind of cast should you use in C#?

Wed, 18 Jun 2008 17:01:04 GMT

C# offers two casting operators: the prefix-cast and the as-cast. Although the two operators compile to different op-codes in the CLR, the practical difference between them is in how they handle failed casts. Prefix-cast throws an exception on cast failure, while as-cast returns null. It's easier to implement correct error handling when you use prefix cast, because it doesn't require manual checks for null values that can cause problems in distant parts of your program. Prefix-cast should be the default cast operator on your fingertips, that you use for everyday situations - reserve as-cast for special cases where performance matters.

Dropping Primary Keys In SQL Server

Fri, 06 Jun 2008 16:22:24 GMT

This article introduces a simple stored procedure that makes it easy to drop the primary key index on a table without knowing the name of the key.

The Curse and Blessings of Dynamic SQL

Fri, 06 Jun 2008 15:35:44 GMT

Nice article about Dynamic SQL for Microsoft's SQL Server. How to do it, why you should do it, and why you shouldn't.

Three Ways To Keep Track Of Context In Silverlight Callbacks

Mon, 02 Jun 2008 17:47:50 GMT

You don't need to think much about context in synchronous programming because the pre-call and post-call parts of a method share a local scope. That's not true in asynchronous programming, where you need to make conscious decisions of where to keep context information. This article describes three effective strategies for keeping track of state.

51+ Best of jQuery Tutorials and Examples

Sat, 26 Apr 2008 14:46:02 GMT

A good summary of jQuery resources

Single Code Path For Asynchronous Functions

Mon, 21 Apr 2008 15:30:01 GMT

Sometimes a function that does an asynchronous action can return without doing asynchronous action: for instance, if an error occurs or it retrieves a value from a cache. If it calls the callback directly, this has a major impact on the flow of execution in the program and can cause subtle bugs to appear. By always initiating an asynchronous callback, you can avoid this problem.

From Developer to Technical Manager

Mon, 21 Apr 2008 04:16:03 GMT

Organizations with an outdated organizational structure have got to wake up and change before it's too late. They will either lose or ruin their people. Either way, the company loses because people are the company.

Get Control of Silverlight Callbacks With Asynchronous Functions

Fri, 18 Apr 2008 20:52:47 GMT

This article presents a simple C# library that can be used to return both exceptions and arbitrary return types, making it possible to compose asynchronous actions out of smaller asynchronous actions

Standalone Silverlight Applications (Moonlight)

Fri, 18 Apr 2008 13:16:03 GMT

"Last year we created a framework to run Silverlight applications as native applications. At the time we called those applications moonlight desklets. The desklets are Silverlight applications that run in standalone mode, with full access to the entire Mono API stack (as opposed to be limited to the .NET subset for the web) and that can optionally render without frames."

The Asynchronous Command Pattern

Mon, 14 Apr 2008 13:19:39 GMT

All http calls in Silverlight Applications are done asynchronously. One of a series of articles about patterns for asynchronous activities in RIA's, this article describes how the Command patten can be used to group both the initiation of a server call and the callback in a single method to clarify the structure of your code.

Do You Really Want to Be a Development Team Leader?

Sun, 13 Apr 2008 09:31:02 GMT

Ask any up and coming developer what they would like to do in the next year or so and you'll invariably hear, "I'd like to become a Development Team Leader". Hopefully most will have actually considered the change of role and be looking for new challenges and ways to contribute more to their chosen profession. However, for some this is an automatic response to a question that is particularly difficult to answer in an industry with no clear career path. For others it's simply a way to move up the pay scale.

Build Reliable SIlverlight Apps With Optimistic Locking

Fri, 04 Apr 2008 16:10:39 GMT

I'm in the middle of updating my Silverlight code to use asynchronous HTTP requests - fortunately, I spent last summer writing a GWT application, where HTTP requests have always been asynchronous, so I've got a library of patterns for solving common problems. For instance, suppose that you're doing a search, and then you're displaying the result of the search. The most reliable way to do this is to use Pattern Zero, which is, do a single request to the server that retrieves all the information - in that case you don't need to worry about what happens if, out of 20 HTTP requests, one fails. Sometimes you can't redesign the client-server protocol, or you'd like to take advantage of caching...

Hosting Silverlight 2.0 in IIS

Wed, 02 Apr 2008 21:16:10 GMT

Describes Silverlight 2.0 hosting issues ...

Unit Testing with Silverlight - the FULL article.

Wed, 09 Apr 2008 15:31:32 GMT

This is the article that ScottGu points to in http://www.dotnetkicks.com/silverlight/ScottGu_Unit_Testing_with_Silverlight , even thought it has more meat than Scott's article.

Subscribing to Silverlight Managed Code events from JavaScript

Wed, 02 Apr 2008 02:07:55 GMT

In Silverlight, it seems that most of the time, you need to reach into the hosting page from the managed world, but what if you want to reach into the managed world from the hosting page? In other words, what if you want to subscribe to a managed event from JavaScript?

Decompiling Silverlight 2 Apps - Enter the XAP

Fri, 28 Mar 2008 15:48:18 GMT

When you build a Silverlight 2 application, you compile your source files (inc. XAML and embedded resources) into assemblies (dlls). Those assemblies (plus any 3rd party ones plus MS assemblies that are not part of Silverlight) are then collected together along with a manifest into a packaged archive - or in other words, a ZIP file. Except, the extension is changed to be a .XAP (pronounced "ZAP").

Managing Concurrency With Asynchronous Http Requests

Thu, 27 Mar 2008 18:34:40 GMT

Microsoft threw Silverlight developers a curveball when it eliminated synchronous http requests. This post outlines the problem and introduces a design pattern which supports the development of simple and reliable client apps that use asynchronous communication.

Firing events with Extension Methods

Fri, 07 Dec 2007 13:31:06 GMT

A different way of firing standard .Net events using Extension Methods