Category: C#

The “with” keyword is a crucial part of a functional programmer’s toolbox, but is sadly lacking in C#. In this blog post, I document the development of a template that will automatically generate a With() method for C# classes.

This entry is part 7 of 11 in the series Mazes For Programmers

As mentioned in the previous post in this series, I decided not to convert his Ruby code into C#, but rather to read his description of the algorithm, then try and write my own code. This way I am forced to understand the algorithm, which is far more productive than simply copying out someone else’s code without really knowing what it does. I had actually seen his code for Aldous-Broder, so had a basic idea of how he went about it, but hadn’t looked at it very closely, so was mainly writing it myself. The end result was actually very similar to his. One thing I discovered when running it was that my mazes were anything other than non-biased. Pretty much every maze I generated had an empty corridor right across the top row, leading me to realise that I had done something wrong. Furthermore, every now and then, the…

One of our main applications involves interacting with a third-party API. Whilst this is generally stable, we have had cases recently where it was throwing random exceptions. We could make the same request with the same parameters multiple times, and sometimes it would work, and sometimes it wouldn’t.

While we left the owners of the third-party API scratching their heads, we realised that the way we handled interaction with such APIs wasn’t robust enough. The first (and most obvious) improvement would simply be to try again.

As this is the sort of thing we’d want to do in a number of places, rather than repeat the same boilerplate code over and over again, we looked for a helper class.

We had a situation in which application users were not checking the customer list before adding new customers, which was resulting in multiple entries for the same customer. We wanted to make it so that when they tried to add a new customer, they would be shown a list of possible duplicates.

It turned out that finding duplicates wasn’t as easy as I thought. I ended up with a helper class that used Metaphones to find similar customers. This post describes the class, and shows how to use it.

I was working with a third-party API, and had to specify a date range object, with a start and date. The problem was, their server was throwing intermittent exceptions when I passed this date filter object as a parameter, claiming that the start date was after the end date. I checked the data, and I was definitely sending a valid date range.

The answer to the problem turned out to involve a little-known (to me at least) part of DateTime. Not the sort of thing you encounter every day, but worth knowing about for the times when it hits you.

I had an odd problem, the resolution of which exposed an interesting bit of information about what goes on under the C# covers that we never usually know.

I had a Linq query that worked fine on its own, but failed at run time when I extracted it into a method and passed in a lambda.

Whilst trying to work out why this was happening, I came to an understanding of the difference between a Func and an Expression, and why it (sometimes) matters.