What has gone into Siderite and made him rave mad? Is he high? Everybody knows that software patterns are all the rage and the only perfect and delicious way to make software. You can't just go "cowboy style" on software, it's an industry after all.

Well, I am not saying that (although you can probably guess from my impression of my virtual/inner critic that I am a bit partial to the cowboy approach). All I am saying is that once you identify a pattern (and yes, to open another parenthesis, a pattern is identified not learnt) one should never stoop low enough to use it. Some software should do that for him!

One good example is the Iterator Pattern. It sounds so grand, but the software implementation of it is the foreach command. Does anyone actually think while iterrating through a collection that they are using a pattern? As I said before, patterns are identified. You think of what you have been doing, see a pattern, make some software to take care of similar situations, then get on to identifying another pattern.

Well, yes, but you can't entrust everything to a software, Siderite! You will bloat your code, create tools that will do less than you wanted and still end up doing your own efficient code. I know, I've seen it before!

Well, thank you, critic! You have just identified a pattern! And any pattern should be solved. And yes, I agree that software can't do everything for you (yet!) and that sometimes the tools that are designed to help us with a problem become a problem themselves. But instead of having "two problems" you have a bad solution to a previous problem. Fixing the solution would fix everything and the problem domain is now one level of abstraction higher.

Stuff like managed code, linq, TDD, ORMs, log4net... just about every new technology I can think of, they are all solutions to patterns, stuff that introduces new problems on a higher level. What C# programmer cares about pointers anymore? (developers should still be aware of the true nature of pointers, but care less about it).

There is one final issue though, the one about the actual detection of patterns. Using "prediscovered" patterns like from the classic Gang of Four book or anything from Martin Fowler is ok, but only if they actually apply to your situation. That in itself shows you have to have a clear image of your activity and to be able to at least recognize patterns when you see them. Sometimes you do work that is so diverse or so slow that you don't remember enough of what you did in order to see there is a repetitive pattern. Or, worse, you do so much work that you don't have time to actually think about it, which I think is the death of every software developer. Well, what then?

Obviously a log (be it a web one or just a simple notebook or computer tracking system) would help. Writing stuff down makes one remember it better. Feeling the need to write about something and then remembering that you have already done so is a clear sign of a pattern. Now it is up to you to find a solution.

Back to the actual title of the post, I recognize there are situations where no automated piece of code can do anything. It's just too human or too complex a problem. That does mean you should solve it, just not with a computer tool. Maybe it is something you need to remember as a good practice or maybe you need to employ skills that are not technical in nature, but should you find a solution, think about it and keep thinking about it: can it be automated? How about now? Now? Now?

After all, the Romans said errare humanum est, sed perseverare diabolicum. The agile bunch named it DRY. It's the same thing: stop wasting time!

WPF Unleashed is a 2006 book in the Unleashed series about the new Microsoft paradigm on visual interaction, written by Adam Nathan. Windows Presentation Foundation is now the default Windows graphics framework, overriding Windows Forms, and it is based on XAML, which is used in Windows desktop applications, Silverlight applications, directly in Internet Explorer and even as a document template.

The book is nicely written, covering all the main characteristics of WPF, the functionality, the problems and tips on stuff that is not so clear. It also contains "Digging deeper" sections where some of the works "under the hood" are revealed. The book focuses more on the XAML implementation (the declarative part) rather that the code one, and I was happy to see that the code was written in C#.

All in all I liked the book and I wish I had more time to parse it completely. So far I've read the basic stuff (without the fancy graphics) so the first 10 chapters and I will wait for a moment of respite so I can detail some of the stuff I found in the book and how to implement them.

There are two things you need to do. First, set the project as having a neutral language. This is done in Visual Studio 2008 by going to the project's properties, selecting Application, clicking on Assembly information and setting the language. However, it doesn't set an UltimateResourceFallbackLocation. So you have to do it manually, by editing the Properties\AssemblyInfo.cs file and adding

[assembly: NeutralResourcesLanguageAttribute("en-US", UltimateResourceFallbackLocation.Satellite)]

The second thing is rather dumb. I haven't found ANY way to do it from Visual Studio. I just edited the csproj file manually. It needs

<UICulture>en-US</UICulture>

set in (under, actually) every <PropertyGroup> in it.

What that does is create a language folder in the bin directory when compiled with a localizable resource file. Using the locBaml utility in the Windows SDK you can turn a resources.dll in the language folder into a CSV, then back into a dll like this:

LocBaml /parse ProjectName.g.en-US.resources /out:en-US.csv
LocBaml /generate ProjectName.resources.dll /trans:fr-CA.csv /cul:fr-CA

.

You will not find locBaml in the Windows SDK folder except maybe as a sample project. The sample project can be downloaded here. Don't forget to compile it!

Some other useful links:
WPF Localization
Localizing WPF Applications using Locbaml
LocBaml + MsBuild + ClickOnce Deployment

Rick Strahl presents an easier and better alternative by using normal resx files! I don't want to copy (too much) from his post, so just read it:
Resx and BAML Resources in WPF

I have seen this used in a couple of places, the most prominent being LInQ. You run a method and then you chain another method to it and so on and so on. It's a nice improvement in readability and a good alternative to static methods.

The clearest example I can give you is on Wikipedia. Check it out. It's actually very easy to use and implement.

Tomorrow I start work on a WPF application that is supposed to be as modular as possible. Since I know almost nothing about WPF or modular applications, I started researching a little bit how it should be done. Basically I found only two ways I cared to expand my research on: Prism (patterns & practices Composite Application Guidance for WPF and Silverlight) and MEF (Managed Extensibility Framework).

Unfortunately I've only had time to do some Prism, although MEF seems to be the way to go. First of all it is a general framework, not limited to WPF/Silverlight and secondly it is used in the new Visual Studio 2010 release. What is amazing is that both frameworks come as freely available opensource.

Ok, back on Prism. The concepts are simple enough, although it takes a while to "get" the way to work with them. Basically you start with:

• a Bootstrapper class - it initializes the Shell and the Catalog
• a Shell - a visual frame where all the modules will be shown
• a Module Catalog - a class that determines which modules will be loaded
• an Inversion of Control Container - class that will determine, through Reflection usually, how to initialize the classes and what parameters they receive
• a RegionManager - class that will connect views with Regions, empty placeholders where views are supposed to be shown
• an EventAggregator - a class that is used to publish events or subscribe to events without referencing the objects that need to do that

Easy right? I don't even need to say more. But just in case you don't have a four digit IQ, better watch this four part video walkthrough:
Creating a modular application using Prism V2 - part 1
Creating a modular application using Prism V2 - part 2
Creating a modular application using Prism V2 - part 3
Creating a modular application using Prism V2 - part 4.

I did try to take the WPF Hands on Labs project and mold it with Prism and it partially worked. The problem I had was with the navigation controls. These work as a web application, where you call the XAML and it has to be a file somewhere, and you have events for the calling and returning from those "pages". I could find no way to encapsulate them so I could build no modules out of them and the whole thing collapsed.

So, for a quick walkthrough on using Prism with WPF.
Creating the core:

1. create a new WPF application project
2. reference the Prism libraries
3. create the Bootstrapper class by inheriting UnityBottstrapper that will determine the Shell (a WPF window class) and set it as the application MainWindow, as well as create the type of ModuleCatalog (either take a default one or inherit one from IModuleCatalog) you want
4. create the layout of the Shell and add region names to the controls you want to host the loaded modules (example <ContentControl Grid.Row="0" Margin="2" Regions:RegionManager.RegionName="SearchRegion"/>

.

Creating a module:

1. create a new library project
2. add a class that inherits IModule
3. the constructor of the IModule can have different parameters, like an IRegionManager, an IUnityContainer, an IEventAggregator and any other types that have been registered in the container (I know it hasn't been initialized in the core, the catalog takes care of that). The IoC container will make sure the parameters are instantiated and passed to the module
4. register views with regions and any additional types with the IoC container in the Initialize method of the module
5. create view classes - WPF controls that have nothing except the graphical layout. Any value displayed, any command bound, any color and any style are bound to the default DataContext. The views will receive a view model class as a constructor parameter which they will set as their DataContext
6. create the view model classes - they also can have any types in the contructor as long as they are registered with the IoC container, stuff like the eventAggregator or a data service or other class that provides the data in the view model.
7. provide all the information needed in the view as public properties in the view model so that they can be bound
8. subscribe or publish events with the event aggregator

As you can see, most of the work is done by the modules, as it should be. They are both communicating and displaying data using the event aggregator and the binding mechanisms of WPF. There are some differences between how WPF and Silverlight approach some issues. The Prism library brings some classes to complement the subset of functionality in Silverlight that are not needed in WPF. However, one can still use those for WPF applications, making a transition from WPF to Silverlight or a mixed project more easily maintained.

The video walkthrough (as well as my own text summary) are based on the rather new Model-View-ViewModel pattern, which many people call a flavour of MVC. It was created specifically for WPF/Silverlight in order to separate behaviour from user interface.

Expect more on this as soon as I unravel it myself.

This is only a bookmark. If you want to know how to do this, read this link from Microsoft: Walkthrough: Using ASP.NET Routing in a Web Forms Application.

Well, you might laugh out loud when you read this, but it is an achievement for me. I wanted to update a table (table A) which had a connection to another table (table B) through a many to many table (table A2B). I had changed A2B to link A to a new table C. I wanted to reflect that change in my Entity Model.

So the first step was to right click on the model and do an "Update Model from Database". Then went through all the steps and clicked Finish. Now entity A has both a collection of Bs and a collection of Cs. I wanted to delete the B collection but, to my chagrin, no delete option was available.

The epiphany came when I managed to select the graphical link from entity A to entity B. The link has the delete option! Which, I have to admit, does make sense. So whenever you want to remove an association between entities... well, select the association and delete it, not the entity properties.

I was trying to do something that is usually a drag: create a query with variable parameters. Something like Google search, where each query has a number of words and you want to search for each of them. How can one do this with Linq? More than that, Linq to Entities, which is pretty much making my life hell nowadays.

The idea would be to start with a IQueryable object and keep adding queries to it. This isn't so bad when you want to do an AND operation between your individual query strings.

var dc=new MyEntities();
var content=dc.Content;
foreach (var filter in filters) content=content.Where(c=>c.Text.Contains(s));

But what if you want to do an OR operation? Then you would want to be able to add stuff to the lambda inside a singe Where method. I won't get into the details, rather give you a link. I am not an expert on this myself, so it would be pointless. The more important thing is that you can do this a lot easier by using a library called LinqKit, which adds some very useful extension methods for Linq, enabling you to dynamically create queries, lambdas, etc.

There are other 'lighter' versions of this method on the Internet, unfortunately most of them are usable only with Linq to SQL, not the Entity Framework. For example I've read an interesting blog entry about this, tried the code, and got an ugly error: "The LINQ expression node type 'Invoke' is not supported in LINQ to Entities". LinqKit also did this in its earlier versions, but the Albahari brothers fixed it. So, as far as I can see, I recommend this library for real life linq composition.

The scenario is this: You use a ScriptManager, a TextBox and a Button and your project is at least referencing the Ajax Control Tookit library. You expect when pressing Enter in the TextBox to get to the button Click event. Instead you get the Microsoft JScript runtime error: ‘this._postBackSettings.async’ is null or not an object javascript error.

I found the solution here: JScript Exception in AJAX Control Toolkit. Basically, put the textbox and the button in a Panel and set the DefaultButton property to the button id.

Today a new AjaxControlToolkit was released. I had hoped that at least they noticed the patch I made the effort of sending them, the one that fixed the dynamic TabPanel issue. But no. Three more controls and probably most of the same old bugs.

Here are more details: New release of the Ajax Control Toolkit

I have been working on a silly little project that involved importing files and then querying the data in a very specific way. And I wanted to do it with the latest technologies so I used The Entity Framework! (imagine a little glowing halo around that name and a choir in the background).

Well, how do I do an efficient import in Linq to Entities? I can't! At most I can instantiate a lot of classes and add them to the DataModel, then SaveChanges. In the background this translates to a lot of insert statements. So it occurred to me that I don't really need Entities here. All I needed is good old fashioned ADO.Net and a SqlBulkCopy object. So I used it like that. A bit of unfortunate translation of objects to a DataTable because the SqlBulkCopy class knowns how to import only a DataTable and I was set.

Ok, now back to the querying the data. I could have used ADO.Net, of course, and in this project, I would probably have been right, but I suspected the requirements for the project will change so I used Entities. It worked like a charm and yes, the requirements did get bigger and stranger as I went. But then I had to select the users that have amassed a number of rows in two related tables (or use a value in the user table) but only if the total number of amassed rows would satisfy a formula based on a string column in the user table that mapped to a certain value stored in the web.config a complicated query. I did it (with some difficulty) in Linq, then I had to solve all kind of weird issues like not being able to compare a class variable with an enum value because the number of types that can be used in a Linq to Entities query is pretty limited at the moment.

Well, was it the best way? I don't know. The generated SQL is something containing a lot of select from select from select sometimes 6 or 7 levels deep. Even the joining is done with select from tables. Shouldn't I have used a stored procedure instead?

To top it off, I listened to a podcast today about Object Databases. They do away with ORMs because there is no relational to begin with. The guy argued that if you need to persist objects, wouldn't an Object Database be more appropriate? And, as reporting would be a bitch when having to query large amounts of tabular data, shouldn't one use a Relational Database for this particular task in the project?

So this is it. It got me thinking. Is the database/data access layer the biggest golden hammer out there? Are we trying to use a single data access model and then build our applications around it like big twisting spaghetti golden nails?

Well, this is a time of great change in my life. First I had to give my cat away, due to medical reasons. I had him for more than 5 years and I really liked him. Now he is living in the countryside, with my parents in law, trying to get some pussy (sorry, couldn't help it :) ) and getting beat up for it by sturdy country female cats.

A few months after I got the cat, I also got a new job, prompting me to write my first blog entry. I was saying then that I am starting my first real software developer job in an Italian company. Now, after almost five years, I am giving away my cat and also changing jobs.

My new company is (hopefully) a place where I can accelerate the rate of my learning and professional development and I will be working there on a Windows desktop WPF+WCF+WF+Entity Framework application. So expect a lot of blog entries about new (for me) technologies. I will be starting work there on the first of June.

On the other hand I don't know if it would be permitted (or I would have the time) to stay available for chat on the blog, so if I don't answer, it's probably because I can't.

Wish me luck, everybody!

VirtualPathUtility.ToAbsolute("~/") = /Site/
HostingEnvironment.MapPath("~/") = c:\InetPub\wwwroot\Site\.
new Uri(HttpContext.Current.Request.Url,VirtualPathUtility.ToAbsolute("~/")).AbsoluteUri = http://server/Site/

A Romanian blogger made a very information link laden post about the new features in .Net 4.0. Check it out: Learning resources for .NET 4.0 new features.

I have seen a small video presentation about the new ASP.Net 3.5 SP1 Script Combining feature. Basically you take a bunch of scripts (like the ones from AjaxControlToolkit) and you bundle them together in a single cacheable file. This decreases the number of concurrent connections on your production site.

The problem was that you had to use some component to see what script files were being loaded and then manually add them to the ScriptManager CompositeScript Scripts collection. And this applies only to correctly registered scripts, not stuff that is embedded in the HTML or what not. Isn't it easier to just parse the generated HTML and then replace the script tags, I thought?

Well, I did a small Response filter/IHttpHandler in about two hours. It would take all consecutive external file references and combine them in a single cached and cacheable call. Then I tested it with Asynchronous postbacks. Epic Fail! The main problem was that the combined scripts would re-register themselves at postback and throw all kinds of errors therefore. But how did they know if they were registered or not before?!

I vaguely remembered an old post of mine about the notifyScriptLoaded function that must be called at the end of every external javascript registrations. Examining the system a little I realised that the flow was like this:

1. register the script (either include it in the HTML in regular render or sending it to the UpdatePanel javascript engine to be registered as a new dynamically script element in the Head page section)
2. if the registration is an async dynamic one, check in an array if the script is loaded and if it is, don't register it
3. in the script call Sys.Application.notifyScriptLoaded() which would take the src of the script element and use it as a key in the above mentioned array to declare it has been loaded

Of course, that means combining all the scripts in a single file registers only that file and you get the original files registered again. Then you get errors like 'Type [something] has already been registered.' or (because there are more than one script file bundled together) 'The script [something] contains multiple calls to Sys.Application.notifyScriptLoaded(). Only one is allowed.'.

Well, I did manage to solve the problem by following these steps:

1. forcefully remove Sys.Application.notifyScriptLoaded() from bundled scripts
2. add Sys.Application.notifyScriptLoaded() at the end of all scripts
3. surround the various scripts with a code that looks like

   sb.AppendFormat(@"if (!window.Sys||!Sys._ScriptLoader||!Sys._ScriptLoader.isScriptLoaded('{0}')) {{
   {1}
   if (window.Array&&Array.add&&window.Sys&&Sys._ScriptLoader) Array.add(Sys._ScriptLoader._getLoadedScripts(), '{2}');
   }}
   ", HttpUtility.HtmlEncode(src), content.Replace("Sys.Application.notifyScriptLoaded();", ";"),src);

.

With problem solved, the AutoScriptCombiner works, but it feels wrong. I wanted to post it on Github, you see, but in the end I've decided not to. However I did learn something about how the Asp.Net Ajax framework functions internally and I wanted to share it with you.