DotNetKicks.com : Stories kicked by paul_houle

First Class Functions And Logical Negation in C#

Tue, 10 Mar 2009 20:33:29 GMT

This article works around the hazards of functional programming C# to develop a first-order function: a function that returns the logical negation of a boolean function, illustrating the power of C# as a functional language once you master certain details of the type system.

Testing an IEnumerable<T> for Distinctness

Sat, 14 Feb 2009 04:37:41 GMT

A simple extension method to tell if the members of an IEnumerable<> are distinct. Can you write a better one?

WebForms or MVC? What about the third option?

Fri, 13 Feb 2009 04:01:19 GMT

I've read a lot of posts and articles about why and when you should choose WebForms or the MVC framework to build your ASP.NET websites. They are all pretty good, but for some reason they forget or ignore the obvious third option - standard ASP.NET without the WebForm.

Inheriting From Silverlight UserControls defined in XAML

Wed, 11 Feb 2009 23:03:55 GMT

UserControls defined with XAML cannot be inherited from directly. This article presents a technique that pushes the XAML-defined control outside the inheritance hierarchy of a containing control, making it possible to derive subclasses.

Control HTML Form Elements From Silverlight

Fri, 23 Jan 2009 21:59:45 GMT

This article contains a simple example of a Silverlight 2 application that controls a hidden HTML form embedded in the host document.

Don't use Delete Links because they create Security Holes

Thu, 22 Jan 2009 07:46:02 GMT

Reasons why you shouldn't use a Delete link in your web application

Whitehouse.gov: an ASP.NET site

Wed, 21 Jan 2009 22:46:03 GMT

This article looks into the JavaScript libraries, HTTP headers, platform and more of the new Whitehouse website. It includes statistics and some suggestions.

Stop Catching Exceptions!

Tue, 05 Aug 2008 21:35:12 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

Sat, 26 Jul 2008 00:14:55 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 23:17:19 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

Fri, 18 Jul 2008 00:45:12 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 19:46:18 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 21:42:35 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

Thu, 26 Jun 2008 05:02:17 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#?

Thu, 19 Jun 2008 01:01:04 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

Sat, 07 Jun 2008 00:22:24 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 23:35:44 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

Tue, 03 Jun 2008 01:47:50 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 22:46:02 GMT

A good summary of jQuery resources

Single Code Path For Asynchronous Functions

Mon, 21 Apr 2008 23:30:01 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 12:16:03 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

Sat, 19 Apr 2008 04:52:47 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 21:16:03 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 21:19:39 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 17:31:02 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.