Part 3: Initialising objects

Consider the following simple class definition:

//Simple client class used to demonstate //C#3 object initialisation class Client {     //Read-write property for the client's name     public string Name { get; set; }     //Read-write property for the client's age     public int Age { get; set; }     //Read-write property for the client's height     public double Height { get; set; }     //Read only property that is True for existing     //clients and False for new clients     public bool IsCurrent { get; private set; } }

A constructor has not been explicitly created for this class so the compiler will generate a default, parameterless one for us. This means that an object can be created and properties assigned inthe way that we are currently used to with C#2

//Create a client object using the default constructor Client firstClient = new Client(); //Assign values to the class properties that have public set methods firstClient.Name = "David"; firstClient.Age = 32; firstClient.Height = 124;

However, with C#3, we are now able to create an object using any of the following methods:

//Construct the object by supplying the client Name Client secondClient =     new Client { Name = "Matthew" }; //Construct the object by supplying //the client Name & Age Client thirdClient =      new Client { Name = "Sarah", Age = 21 }; //Construct the object by supplying //the client Name & Height Client fourthClient =     new Client { Name = "Daniel", Height = 131 }; //Construct the object by supplying //the client Height only Client fifthClient = new Client { Height = 108 };

This is essentially identical to creating a client object with the default constructor and then calling each property set method as appropriate. Looking at the disassembled code shows us what isactually happening for these client objects.

Client <>g__initLocal0 = new Client(); <>g__initLocal0.Name = "Matthew"; Client secondClient = <>g__initLocal0; Client <>g__initLocal1 = new Client(); <>g__initLocal1.Name = "Sarah"; <>g__initLocal1.Age = 0x15; Client thirdClient =<>g__initLocal1; Client <>g__initLocal2 = new Client(); <>g__initLocal2.Name = "Daniel"; <>g__initLocal2.Height = 131.0; Client fourthClient = <>g__initLocal2; Client <>g__initLocal3 = new Client(); <>g__initLocal3.Height = 108.0; Client fifthClient = <>g__initLocal3;

As the code above shows, each client is constructed using the default constructor and then the property set methods are called as necessary. Of course, we cannot specify a value for IsCurrent when creating a client object because the set property is marked private (as shown in the first code snippet). Trying to do so will generate a compile time error of something like: The property orindexer ‘Blog.Client.IsCurrent’ cannot be used in this context because the set accessor is inaccessible.

Part 4: Implicit types

Part 2: Automatically implemented properties

C#2 provides the ability to create properties that encapsulate class member variables; the following code provides a simple example:

//Private member variable to store the client name private string name; //Read-write property for the client?s name public string Name {     get     {         return name;     }     set     {         name = value;     } }

The idea here is that the property prevents the class variable from being accessed directly. A property can be made read only as follows; this is simply a property that does not have a set statement.

// Read only property that returns the client?s name public string Name {     get     {         return name;     } }

C#3 provides a shortcut syntax for creating class variables and associated properties; the first code example can be shortened to:

// Shortcut syntax for creating properties //and underlying member variables public string Name { get; set; }

And of course, the principle of read only (or write only for that matter) properties is also supported using this new syntax:

// Shortcut syntax for creating properties and underlying //member variables (this time ClientName is read-only) public string Name { get; private set; }

For this shortened syntax, the compiler actually generates all of the required code behind the scenes. So in effect, you end up with exactly the same code that you would have got if you had written it using the available syntax of C#2. The code below shows the MSIL that is generated from the source code; note the use of the [CompilerGenerated] attribute that decorates the code.

[CompilerGenerated] private string k__BackingField; public string Name {      [CompilerGenerated]      get      {          return this.k__BackingField;      }     [CompilerGenerated]     set     {         this.k__BackingField = value;     } }

Automatically implemented properties provide a way to quickly expose class member variables; we will examine this feature more in the next article.

Part 3: Initialising objects

The newbie guide to C#3, Part 1: Overview

This short series of articles gives you an overview of the new features provided by C#3. The articles are peppered with simple code examples that you can copy directly into a C#3 editor to try them out for yourself. At the end of each article, a link is provided to a standalone class that contains fully commented examples of the features that have been discussed.

The information presented here won't make you a C# guru but they will give you an appetite for the new features that have been added to the language.

Part 2: Automatically implemented properties
Part 3: Initialising objects
Part 4: Implicit types

Smaller steps, greater strides ... revisited

I often see colleagues of mine struggling to add new features to our software; I often see workmates struggling to rectify the existing features of our solutions. Frustrated managers wonder why code that only took 2 or 3 months to write has stagnated in an endless UAT cycle with little hope of breaking free. Small change requests end up taking 3 times longer than the estimates that helped justify the change in the first place. Customers, initially used to timely releases grow increasingly impatient as release periods are extended or bug littered deployments are made on schedule.

Why does this happen? Optimism play a small role in this predicament; as software developers we almost always underestimate the tasks that we are given. Pick up any Steve McConnel book and look at the graphs - it's an industry wide phenomenon. Although this plays a contributory role, it is by no means the root cause of the problem. I rarely see developers having difficulty putting new code together; I guess there's no getting away from the fact that software is easy to write but difficult to maintain. There is also the question of motivation, nobody likes to work with scrappy code; as Pragmatic Programmers we shouldn't have to live with broken windows.

So why do we write poor, complex, undocumented code when we know it will eventually come back to haunt us (or more likely someone else on the team). Sometimes it's laziness but I think there is an inherent trait that developers possess - we are always keen to see the results of our ideas. We start with the best of intentions but as we gain momentum we see the outcome beginning to materialise. We write code more quickly, absolutely determined to come back and add the comments and write the unit tests. It's not true TDD anymore but the result is almost tangible now, just a few more lines and we'll be home and dry. Sure we have some tidy up code to complete, exception handling needs to be incorporated and then there's the diagnostics namespace to worry about...but just a few more lines and the refactoring can begin...just a few more lines...

And so the problem begins. before we get chance to paint over the cracks a system bug is reported, the requirements change and a different solution is screaming for attention. We no longer have time to commit to our solution, there is no longer an end point to reach for - just boring changes and bug fixes. The momentum disappears and we move on to a newer, brighter challenge vowing never to cut corners again. Somebody else is assigned to the project, sees all the broken windows in the neighbourhood and continues to break a few of their own. Which leads us back to our frustrated managers and impatient customers.

There are many methodologies that address these issues and offer a strategy for preventing them. Personally I think the methodology we need is a simple injection of discipline. After all, if you can't be bothered to add a single function header now, will you really come back and add 100 once your class is complete? If the code seems to work ok will you really find the time to go back and write the unit tests. Even if you do, the opportunity to confirm your understanding of the problem before the coding started disappeared when the TDD process stopped.

As with any habit, good or bad, it can take a lot of discipline and effort to stop. The same is true, in my opinion, with software development practises. Jumping ahead may seem to shorten the journey but smaller steps really do lead to greater strides especially in a well disciplined environment.

It takes time to make a decision

Some people describe software development as a manufacturing process. Basically you take a recipe, try it out a few times and once you are happy with the ingredients and the cooking process you write it down and pass it on to your eager coders. Over time you collect a whole book of recipes that can be easily followed, producing code that is both repeatable and reusable. Software restaurants announce ticker tape openings around the globe to serve up cheap and reliable cookie cutter software solutions. Recipe for success? Actually, past experience tells us that more often than not it is a recipe for disaster.

The manufacturing process needs to guarantee repeatable results and this is very difficult given the amount of human intervention that programming typically involves. Of course, there are now many utilities that generate, parse, check, analyse and generally prettify source code but it's still essentially a solo practise between the developer and the IDE (apologies to all you XP pair programmers out there). There is also the issue of code maintenance to consider, generated code is not the prettiest of creations and, whilst it's fine when it works, any subtle imperfections are often very difficult to isolate and rectify.

Some people describe software development as an artform. Each contributor adds their own creative interpretation of requirements, applies keyboard brushstrokes to their electronic canvas and steps back to admire yet another unique creation. No two pixel paintings are the same; programmers the world over write different code to achieve the same objective. Even individual coders write the same routines differently, with or without varying degrees of standards and procedures, many times during their illustrious careers. An artistic masterclass? Very often this approach generates code that may be inventive but is seldom practical and rarely maintainable.

The problem here is consistency; code is produced that can be difficult to maintain where the layout of each class looks very different to its neighbours. There are a number of architectural decisions and considerations that a developer has to make that exist outside of what is generally perceived as the 'system design'. Does a particular piece of logic sit in the database layer or the business layer? How are exceptions handled? Should a method be instanced or static? Do you choose an interface or an abstract base class? In reality your code is simply a string of statements, loops and conditions but the potential number of combinations are astronomical even within a relatively small code base. Coding standards and recommended practises can help to reduce the confusion, code generation can produce generic classes and components and design patterns provide some level of guidance but dividing a limitless number of possibilities by any given factor still leaves a limitless number of possibilities.

So should we strive for a repeatable and consistent, painting by numbers development process where creativity and initiative are completely removed from the programming equation? Or do we promote flexibility and encourage our development teams to express their creativity and inventiveness in new and inspiring ways? Is there some magical, middle ground that satisfies the developer's creative aspirations whilst still adhering to repeatable templates, design patterns and agreed best practises?

This blog is littered with questions but unfortunately devoid of answers; each question corresponds to at least one, and often very many decisions. It is ironic that the decision making process is a key factor in making programming an interesting practise. It is also a subtantial contributor to the problems and complexities that lurk beneath the surface of even the most trivial of solutions.

Decisions take time ... so less choice, less freedom and fewer choices must surely facilitate a better programming environment...or do they?

The wow is not yet!

My house, for all its sins, has good quality window frames that really were built to last. The underlying woodwork is preserved against the elements by a tough primer, several layers of resilient undercoat and a highly polished gloss exterior. The smooth surface hides a multitude of hidden stratas; each coat of paint provides a robust foundation for the neighbouring coat above it.

Many times, the effects of driving rain, wintery gales and sub-zero temperatures have been wiped away with the stroke of a cloth and the occasional squirt of polish. However, over time, the relentless onslaught of the weather gradually erodes this painted armour. The once pristine surface begins to look aged and imperfect and the challenging maintenance cycle begins.

With care and attention, the frame can be restored but each repair introduces subtle imperfections that accumulate over time. Of course, other parts of a house are prone to this gradual degradation and even the most dilligent handymen struggle to keep everything in showroom condition. Corners are cut and compromises are made to patch up a problem because of other more pressing maintenance and decorating issues. Ultimately, the patching, redecorating and restoration can no longer resolve the effects of an ever ticking clock and the window frames have to be replaced.

It is at this point that the inevitable analogy with PC based windows can be made. The question is, does Vista apply just one coat too many in the continuing search for a new glossy finish? Sure it looks pretty with its 3 dimensional application browsing and fancy widgets but look beneath the surface and perhaps the undercoat is beginning to crumble a little. For my laptop, applications run more slowly when they can actually be bothered to run at all. The entire system locks up with more regularity than ever before and refuses to reanimate itself unless rebooted. The continual need to reaffirm my identity, even as a system administrator, is annoying at best and common tools and features have been juggled around to the point of obscurity. Many of the once promised features have been omitted leaving a pretty shell with an aging interior.

Everyone around me is busily reinstalling Windows XP as new hardware manufacturers grudgingly offer alternative operating systems.

I have always supported Microsoft in their endeavours and continue to do so but the problem of beauty only being skin deep remains. A pretty face will always turn heads but this fascination soon fades especially when there seems to be little inner depth below the surface. My expectations of Vista have far outweighed my experience and I can only hope the disappointment of this flagship product is not repeated. The wow is most definitely not now!

Preparation is everything

During a particularly engaging World of Warcraft quest last month I decided that it was time to find a 'proper' hobby. This dawned on me as my fellow guild members started calling me old timer and logging off at 7pm on school nights. I'd always had a distant fascination with astronomy and chose to prefer star gazing into the heavens as a more intellectual alternative to star gazing in Hello magazine.

Armed with my battered credit card I went online shopping and 2 weeks later my new telescope arrived with built in gps device, object database and goto facility. My enthusiasm was not diluted even by the prospect of a multi-lingual, 200 page instruction manual.

After a hasty assembly I cursed and scowled my way through the remaining 5 hrs of daylight hoping sunset would deliver me a cloud free northern hemisphere. My prayers were answered and I found myself wrestling with a 100 pound glass / metallic hybrid which possibly outweighed the instruction booklet.

The next problem was to point the telescope at true (not magnetic) North, ensure it was aligned horizontally and then validate its position with one or two predetermined reference stars. This seemed like a daunting prospect but the next 30 minutes reaffirmed my belief in technology. The attached handset was intuitive to use, it found my local time and location (using the inbuilt gps device), and happily pointed the scope at true North. Whirring back into motion, the motorised mount pointed me at a reference star from its database of truly stellar proportions, a slight manual adjustment and I was ready to go.

This typifies, for me, one of the major benefit of software systems. They help you prepare quickly and efficiently for the real task at hand. Don't get me wrong, watching a telescope engaged in an automated, robotic dance while it aligns itself with an object 200 light years away is certainly an impressive experience...the first time around. On a cold, damp night it soon becomes a process that you would happily perform instantly given the opportunity. The real experience is looking at the comet battered surface of the moon or the perfectly formed rings around Saturn.

So do software systems prepare us for the tasks we need to complete and the activities that we enjoy rather than performing them for us? I would like to think so. After all, once your forecast reports have been scheduled for printing and your manangement reports have been automatically generated the real work can begin. Efficiency improvement discussions, marketing campaign brainstorming sessions, sponsor driven board meetings, the day to day human collaboration that constitutes the organic nature of an organisation...these are the processes that really make a difference. It's comforting to think the polished oak table that decorates the board room will not be replaced by server racks and an air conditioning system. So perhaps we should think about how our systems can assist rather than replace next time we are struggling to put realistic requirements together. It could save a lot of effort thinking about something that really isn't necessary.

And if the monthly reports find their way to the MD's desk a little earlier because of the new accounting system then so much the better. You can contemplate how software helps rather than replaces your daily functions as you walk down the first fairway on your sunny afternoon off. In fact, thinking about it; preparation isn't everything - it's just something that software systems are particularly good at. :-)