Monthly Archives: September 2007

Books, C#

C# in Depth: Chapters 4 and 5 now available in MEAP

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Chapters 4 and 5 of the book have now been made available for early access.

 

Chapter 4 – Saying nothing with nullable types

Nullable types depend heavily on generics (described in chapter 3) and require both language and runtime changes. In this chapter I explore the problem they solve, the types involved (including runtime changes) and the C# changes (int? meaning Nullable<int> and the various operators and conversions available). I also cover a couple of uses of nullable types which haven’t necessarily hit the mainstream, but can prove useful – the comparisons I wrote about in this blog a little while ago, and using nullable types as an alternative to out parameters for the TryXXX pattern.

 

Chapter 5 – Fast-tracked delegates

C# 3 relies on delegates a lot. You can’t do any real LINQ work without them. C# 2 laid a lot of the groundwork for the lambda expressions available in C# 2 when it introduced anonymous methods. There are other changes in C# 2 which improve delegates, however – and there are more methods in the .NET 2.0 framework which take advantage of delegates than there were in .NET 1.1. (I’m thinking particularly of List<T>.)

I cover all the improvements in this chapter, but most of the chatper is given over to anonymous methods, and the handling of captured variables in particular. Without wishing to sound like a spoilsport, the use of captured variables can look like magic. Captured variables are still just as useful when the magic is explained away, and they’re somewhat less scary!

 

More chapters to come soon, I expect – when chapters 6 and 7 are released, that will cover the whole of C# 2.

C#, General

Announcement: Partnership with Iterative Training

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I’m delighted to announce my association with Iterative Training, a new .NET training company in the UK. It’s been founded by a colleague of mine and his girlfriend, and ran its first course earlier in the year – a WCF Master Class taught by Juval Löwy of IDesign. As you can tell from its starting point, Iterative Training is dedicated to providing really top notch training from genuine experts.

Where do I fit in? Well, I’m promoting the company on my website (the GoogleAds are now replaced with course adverts – but still without getting in the way of the content, I hope) and will be attending the last couple of days of TechEd in Barcelona to give some visibility to what we’re doing. Beyond that, I may well end up giving “taster talks” at user groups, and possibly even end up as a very occasional trainer. Who knows what the future holds?

I’m really excited about this opportunity to see more of the training side of development, and hopefully contribute to it. I have no idea what proportion of my readership comes from the UK, but I hope that if you do, and if you’re interested in some of the new .NET technologies, that you’ll have a look at the courses on offer and hopefully find something of interest. If you have suggestions for courses we should be offering but aren’t, we’d love to hear them – although we’re trying to keep to a relatively light schedule for the first year or so, focusing on quality rather than quantity.

None of this changes my existing situation: I will still keep up this blog and my articles, the book is still in progress, and I’m still in permanent employment. It’s expanding rather than replacing my range of activities :)

Java

Java isn’t an acronym

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Just a quickie while I remember. A pet peeve of mine has surfaced again recently, while reading some CVs.

Java, the programming language, is just written “Java”. It’s not an acronym. There’s no need to write it as “JAVA”. That just looks shouty and somewhat silly. Why do so many people get it wrong? While we’re at it, why does it irritate me so much to see it written the wrong way?

Books, C#

Announcing “C# in Depth”

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Finally, I can properly talk about what I’ve been working on for about the last 6 months. The book I’ve been writing is called “C# in Depth” and it’s being published by Manning (just like Groovy in Action was). It’s about C# 2 and 3, and pretty much just C# 2 and 3. In particular, it’s aimed at people who already know C# 1 at least reasonably well. I believe there are plenty of people who are comfortable with C# 1 but either don’t know C# 2 at all or are familiar with it but have gaps in their experience. It’s for these people (hopefully many of whom are reading this blog!) that I’ve been writing.

I don’t know whether there are other books in progress in the same vein. I strongly suspect there will be several books which cover C# from scratch – and end up either skimping on detail, or being unliftable tomes. There may be some books which cover just C# 3 – which will make them less useful for developers who may not get to use C# 3 for a while, or don’t have enough C# 2 experience to fully appreciate C# 3.

Anyway, the first few chapters are now available in MEAP (Manning Early Access Program) at the C# in Depth website. The first chapter is available free, and you can get hold of the others by paying for either the e-book or the hard copy now. Obviously you won’t get the hard copy until it’s published, but you’ll get the electronic version as it gets updated, chapter by chapter. Here’s a quick rundown of the chapters which are available so far:

Chapter 1 – The changing face of C# development

This chapter is mostly introductory material, as you’d expect. There’s an outline and examples of some of the biggest features, a brief history of C# and .NET, and a little look at the “snippet” style of listings used in the rest of the book.

Chapter 2 – Core foundations: building on C#1

Although the rest of the book is written about C# 2 and 3, I wanted to make sure that all the readers had a good understanding of three aspects of C# 1: delegates, value/reference types, and the nature of C#’s type system. While all of them are important in C# 1, they’re often misunderstood – particularly delegates, which aren’t used very often in C# 1 beyond event handling. Delegates are friendlier in C# 2, and understanding C# 3 is practically impossible without a good handle on them.

Chapter 3 – Parameterized typing with generics

Generics are the biggest feature of C# 2, and the biggest change in the .NET 2.0 CLR as well. In this chapter I look at why they’re needed, how to use existing generic types/methods as well as how to write your own. Some more advanced topics are covered such as thinking about what the runtime does with generic types, and I examine the generic collection types provided by .NET 2.0. Finally, I cover some of the limitations of C# generics in C#, including the lack of covariance/contravariance (which is one of the most frequently asked questions in the C# newsgroup).

 

So, I hope that’s whetted your appetite a bit. Obviously I’d be overjoyed if all of you lovely people bought a copy of the book, but even if you don’t want to part with any cash right now, I’d still appreciate comments. Rather than talking about the book here in my blog, it’s best to use the author forum which has been set up for that very purpose. If you want to keep things private, you can email me directly of course.

Having worked this hard on the book, I reserve the right to plug it on this blog every so often – but I promise not to turn the blog into just a stream of adverts :)

C#

How does everyone else mock web services?

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Here’s a situation I ran into a while ago, and will no doubt run into many, many times in the future:

  1. I implement a web service (in .NET 2.0)
  2. I add a web reference in another project
  3. I make calls to the web service
  4. I want to be able to test those calls, and how the client will react to different results

Now, this is an ideal situation for mocks or stubs – except that the proxy code generated by Visual Studio (or rather, wsdl.exe) doesn’t include an interface, which makes it trickier to mock. (I can’t remember whether the methods generated are even virtual or not.) Fortunately, it does write it out as a partial class in VS2005, which makes life a lot easier.

I solved this problem with a home-grown tool, which went through the following phases as a pre-build step:

  1. Check whether the web reference proxy code (specified as a parameter to the tool) has already been modified. (I use a comment at the top of the file to indicate that it’s already been processed.) If it has, stop.
  2. Load the file line by line, using a regular expression (yes, I do use them sometimes) to spot method signature.
  3. Begin a new file with the “I’m modified” comment.
  4. Write out all the old code.
  5. Write out all the method signatures as a new interface.
  6. Write out an extra partial class declaration which just makes the existing class implement the interface.

None of this is too hard – and it could be done with separate files instead of rewriting the generated one, etc. However, I was very surprised when I didn’t find such a tool on the net. (To release one myself I’d probably rewrite it so as to be totally mine rather than my company’s.)

Is there a tool out there which everyone uses and I’ve mysteriously not heard of? (Unlikely.)

Does everyone else take a different approach entirely? (Quite possible.)

Do people just not test their web service calls? (Likely for many people, but not for true TDD-ers, surely.)

C#, General

Writing user interfaces

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Some of you may know that I don’t do a lot of user interface work. Well, in the last couple of weeks I’ve been doing little but user interface work. I thought it might be time to share a few reflections.

Designers

The designer in VS 2005 is actually very good – for a designer. It still has its “thou shalt not touch this bit of code” which of course you then have to touch in order to include some controls which aren’t in the toolbox, but overall it’s pretty reasonable. I particularly like the “GenerateMember” property it uses to decide whether or not to create a member variable for controls. No more silly label variables for no reason!

One day I’ll be able to use WPF/XAML, which is of course another step up again, but until then this isn’t too bad.

TableLayoutPanel

Hooray, a half-decent layout in WinForms. Whatever people may say, just using Dock and Anchor doesn’t give enough control over layout in my view. Lining things up with absolute positioning should have been a thing of the past years ago.

TableLayoutPanel appears to have some significant shortcomings, however. In particular, I was in a situation where it would have been really nice if TLP allocated all the “Absolute” sizes, then gave as much as possible to the AutoSize rows, then gave any spare to the percentage rows. However, it goes top to bottom, left to right. Basically I wanted a couple of buttons below a multi-line label, and for the label to become a scrolling area if there wasn’t enough room for it, with the buttons always present just below the label. Maybe there’s a way to lay this out the way I want, but having sworn over it for most of an afternoon, I’ve given up.

Scrolling is also a pain – it tooks me a long time to get any scrollbars to appear when I wanted, and I still don’t know exactly what triggered it suddenly working. Even now they aren’t quite right, as the appearance of a vertical scrollbar forces a horizontal scrollbar to let you get at the bit of the panel which is now taken up by the vertical scrollbar – even if there’s nothing there! All very frustrating.

Overall architecture

I really suck at this. I’m trying to separate everything out appropriately, but I don’t know enough about it to cope when things get tricky. All the samples of MVC, MVP, Humble Dialog etc are fine when they’re doing relatively simple stuff, but it feels like UI is particularly prone to “I know I shouldn’t have this logic here really, but it’s much easier than doing it properly…” Hmm.

Frustration/Joy

I have really mixed feelings about the satisfaction derived from UI. A lot of the time it seems like very slow work – implementing a small UI feature seems to take a lot longer than implementing a small server-side feature – but when it’s working, it’s very visible. You can show people the results. Just demonstrating hundreds of working unit tests and a few database tables filled with data doesn’t have nearly as much of a pull. I think a prototype UI (not prototyping the real UI, just enough to demonstrate backend features) is possibly the way forward here.

Basically, I suspect I’ll never be a GUI person at my core. I can grow to be passably good at it, but I suspect that you have to keep working at it for a high proportion of your time to know all the gotchas and tricks involved and keep a clean design.

 

In other news – the book is still coming along. Sorry to have kept so quiet about it, but I’m hoping I’ll be able to announce something properly (and tangibly) fairly soon.