Author Archives: Keith Dahlby

About Keith Dahlby

I'm a .NET developer, Git enthusiast and language geek from Cedar Rapids, IA. I work as a software guru at J&P Cycles and studied Human-Computer Interaction at Iowa State University.

Is Functional Abstraction Too Clever?

Posted on October 17, 2009 by Keith Dahlby

I received a rather interesting comment on a recent Stack Overflow answer: This code seems too clever by half. Is it art? – PeterAllenWebb The code in question was a functional solution to an algorithm described approximately as follows: Draw n−1 … Continue reading →

Posted in Functional Programming | 12 Comments

Refactoring with Iterators: Prime Factors

Posted on September 30, 2009 by Keith Dahlby

Andrew Woodward recently posted a comparison of his test-driven Prime Factors solution to one written by Uncle Bob. In the comments, someone suggested that Andrew use an iterator instead so I thought I’d give it a try. First, let’s repost … Continue reading →

Posted in Iterators, Refactoring | 2 Comments

Hacking LINQ Expressions: Join With Comparer

Posted on September 19, 2009 by Keith Dahlby

In this installment of my Hacking LINQ series we’ll take a look at providing an IEqualityComparer for use in a LINQ join clause. The Problem Many of the Standard Query Operators require comparing sequence elements and the default query providers … Continue reading →

Posted in Hacking LINQ, LINQ | Leave a comment

Hacking LINQ Expressions: Select With Index

Posted on September 15, 2009 by Keith Dahlby

First, a point of clarification: I use LINQ Expressions to mean (Language-INtegrated) Query Expressions (the language feature) rather than Expression Trees (the .NET 3.5 library in System.Linq.Expressions). So what do I mean by “Hacking LINQ Expressions”? Quite simply, I’m not … Continue reading →

Posted in Hacking LINQ, LINQ | 3 Comments

Functional Construction for ASP.NET Web Forms

Posted on September 13, 2009 by Keith Dahlby

System.Xml.Linq (a.k.a. LINQ to XML) introduces a nifty approach to creating XML elements called functional construction. I’m not entirely sure why they call it functional given that constructing an object graph is a decidedly non-functional task in the traditional sense … Continue reading →

Posted in ASP.NET, Functional Construction | Leave a comment

Simplifying LazyLinq

Posted on September 13, 2009 by Keith Dahlby

This is the fourth in a series of posts on LazyLinq, a wrapper to support lazy initialization and deferred disposal of a LINQ query context: Introducing LazyLinq: Overview Introducing LazyLinq: Internals Introducing LazyLinq: Queryability Simplifying LazyLinq Introducing LazyLinq: Lazy DataContext … Continue reading →

Posted in ILazyContext, ILazyQueryable, LazyLinq, LINQ, LINQ to SQL, Queryable | Leave a comment

Introducing LazyLinq: Queryability

Posted on August 21, 2009 by Keith Dahlby

This is the third in a series of posts on LazyLinq, a wrapper to support lazy initialization and deferred disposal of a LINQ query context: Introducing LazyLinq: Overview Introducing LazyLinq: Internals Introducing LazyLinq: Queryability Simplifying LazyLinq Introducing LazyLinq: Lazy DataContext … Continue reading →

Posted in ILazyQueryable, LazyLinq, LINQ, Queryable | Leave a comment

Introducing LazyLinq: Internals

Posted on August 18, 2009 by Keith Dahlby

This is the second in a series of posts on LazyLinq, a wrapper to support lazy initialization and deferred disposal of a LINQ query context: Introducing LazyLinq: Overview Introducing LazyLinq: Internals Introducing LazyLinq: Queryability Simplifying LazyLinq Introducing LazyLinq: Lazy DataContext … Continue reading →

Posted in Uncategorized | Leave a comment

Introducing LazyLinq: Overview

Posted on August 6, 2009 by Keith Dahlby

This is the first in a series of posts on LazyLinq, a wrapper to support lazy initialization and deferred disposal of a LINQ query context, including LINQ to SQL’s DataContext: Introducing LazyLinq: Overview Introducing LazyLinq: Internals Introducing LazyLinq: Queryability Simplifying … Continue reading →

Posted in DataContext, Expression Trees, LazyLinq, LINQ, LINQ to SQL | Leave a comment

Using IDisposables with LINQ

Posted on July 23, 2009 by Keith Dahlby

Objects that implement IDisposable are everywhere. The interface even gets its own language features (C#, VB, F#). However, LINQ throws a few wrenches into things: LINQ’s query syntax depends on expressions; using blocks are statements. When querying a sequence of … Continue reading →

Posted in IDisposable, LINQ, LINQ to SQL | 6 Comments