Inspecting System.Xml.dll reveals it references System..dll, inspecting System.dll reveals it references System.Xml.dll. As far as I know, it's not possible to create circular references. Is this a trick from Microsoft? If the two assemblies reference each other, why create two seperate ones?
There have been voices talking about the lack of updates to the .NET Framework and Visual Studio, especially since we learnt that the next versions won't be released before 2005. Microsoft did not release fixes while some well known problems exist. If you don't know the "Help | Check for Updates" command in Visual Studio, it's not worth looking for it, you won't find updates there. All we got was the .NET Framework 1.1 and Visual Studio 7.1.
I may have an idea why there is no lighter and interim updates: maybe it's not easy or even possible to release updates!
How did I come to that conclusion?
Let's take the following situation with one assembly referencing another:
Not trying to compete with Rory here ;-)
If you want to update Ass1, and have Ass2 use that updated assembly, you have to update Ass2. This is because each assembly references the other ones using their name and their version. If you don't update Ass2, it will continue to use Ass1 version 1.0, the version it has been built with.
If you take that to the Framework level, it's all a bowl of spaghetti with dependencies everywhere. Don't forget also that applications, components and Visual Studio are also part of this Italian delicacy and tied to it as well.
Releasing a fix to one assembly requires releasing new versions of all the assemblies referencing it. If you touch a part of the framework, you need to review the whole of it. This is not bad, this is even a good thing in fact. This ensures that the framework is consistent. But it is understandable that Microsoft cannot release multiple version of the framework. We all know how difficult it is to get a new version of the framework (like any other software, especially from some companies) to be validated by administrators. Imagine what a mess it would be if there were versions 1.2 and 1.3 in addition to versions 1.0 and 1.1... You would also have to update your application so they benefit from the new versions.
Do I miss something? What solution do you see to that problem?
Trying to get rid of the DLL Hell, are we locked in an Assembly Versioning Hell?
When you work with configuration files throughout the framework and the application blocks, you encounter assembly qualified names. Assembly qualified names (AQN) look like this: "MyNamespace.MyClass, MyAssembly". This is useful, because a string like this gives you everything you need to find a type. You can simply use Type.GetType() to access a type, based on its AQN.
I was searching for a method to parse AQNs for my own configuration files because I need to call Activator.CreateInstance(string, string), which expects assembly name and type name broken apart.
Well, I looked in the framework, and I found several methods.
There is Assembly.ParseTypeName(). There is TypeInfo.ParseTypeAndAssembly(). There is RemotingXmlConfigFileParser.ParseType().
The first one is internal to the CLR, the others have implementations of their own. Maybe more implementation are scattered around the framework, and maybe more in application blocks or other apps.
I'd say it's time for some refactoring to create one and only method in the framework. It's not because writing this method is difficult, but it's violating the DRY principle. What if AQNs change in .NET 3.2?
It would be nice if this method gets public too so we don't have to write our own...
Now that the dates for Whidbey and Yukon have slipped again (Visual Studio 2004 is now Visual Studio 2005, and VS2005 is now VS2006 or VS2007!), maybe we'll see less madness about all the fabulous novelties in Whidbey, Yukon and Longhorn. Looks like we won't be deploying on Longhorn before 2009. That's 5 (FIVE) years from now. Unless you live in the future, maybe you'd better focus on the now more than on the cool
Update: the title of this post should probably be "Slowing down your white horses" :-)
Do you think a rental model for software could exist?
There are some software that I use only occasionally, such as disk partition managers, disk defragmenters, benchmarking tools... These tools can't be used online for obvious reasons, so they'd still have to be downloaded. No ASP model.
But still, maybe I could avoid buying these products, but instead rent them like I could rent a car or a DVD?
Sami Jaber published a new article on DotNetGuru (in French,
but to be translated soon on the English DotNetGuru- Update: now available in English) about lightweight containers such as Pico, Spring, Avalon or HiveMind. As a complete gringo to J2EE, this notion of containers and Inversion of Control was completely new to me.
Well, maybe it's not so new to me because it reminds me of something I did recently.
I have this Document object that contains some data structures. Let's call those, Struct1 and Struct2. These structures need to be loaded from some database somewhere. For the sake of simplicity, let's forget how the datasources are identified. What is important is that the data structures be completely independent from these data sources, mainly because we could want the data in an SQL database, in XML files, or whatever. This is why I use Data Loader Objects.
Here is how it works when the Document object needs to be loaded:
The data structures are contained in an InstanceCollection object. This instance collection is put into a new instance collection, under the ID Targets. The loaders then get created in this new instance collection, based on a configuration file. The loaders are created using a Provider pattern (I just call it the AbstractFactory pattern).
The loaders are automagically connected to their respective data structure with property setters. As the following configuration file states, the Loader1.Target property points to Struct1 in Targets ("Targets/Struct1").
Once this is set up, the loaders get executed and fill their respective data structure with data.
With this solution, the data structures are isolated from the data sources, all is configured, extensible and customizable.
Looks like that will be a busy week-end :-)
That's right, two blue boxes...
Eric Gunnerson published an article in which he tests the different ways of invoking a method.
Pierrick Gourlain (no weblog yet...) updated the code to include tests with new cases: virtual, virtual+interface, static, MethodInfo.
I won't publish the results here, you should download the code and run the tests by yourself.
You absolutely have to try running the tests with a Release build and with a Debug build. What do you observe?
BTW, do you deploy your assemblies as Debug or Release builds?
La commande du jour: I just discovered the Edit | Find and Replace | Find Symbol command in Visual Studio. Yep, new things every day.
Here is its description: Searches for objects (namespaces, classes, structures, interfaces, types, enums, and so forth) and their members (properties, methods, events, variables, constants, enum items, and so forth) in the current scope.
Quite useful to jump to a class definition based on a name you type in. It even lists the references (where this class is used) for you. Note that there is also the Quick Find Symbol command, which does the same without displaying the dialog box.
BTW, I use the right click | Go To Definition (F12) command a lot, but I had never came accross Find Symbol yet.
Toss in View.NavigateBackward and View.NavigateBackward, and you're ready for quick and fluid code navigation.
As a followup to my post yesterday with Martin Fowler's quote, you can check out SoftwareQuotes. Great site. If you know some quotes that aren't there, you're encouraged to contribute...
Thanks Hákon for the pointer and the site.
I think I've seen a good quote from Anders Hejlsberg once, but I can't find it back. If ever you know it...
Are these the new easter eggs?
Ok, this is what you can do with the Command Window... But the small Find textbox is handy for commands like open. You just have to know you can do that!
What useful commands or macros do you use in the Command Window or in the Find textbox?
Citation du jour:
“Any fool can write code that a computer can understand. Good programmers write code that humans can understand.”
-Martin Fowler et al, Refactoring: Improving the Design of Existing Code, 1999
I found this back while re-reading our code conventions. This quote is a good introduction for such a document.