Thursday, September 30, 2010

My Prism Journey (Part 3)

It’s Me, Not You

WPF’s bare controls are decent, but not always as robust as people need or want.  I initially setup my Shell using the basic Grid component on a Window.  Of course I was and still am in the learning phase, but as my project becomes more “real”, I realize that I should probably start using the components that’ll actually be needed once my project hits our production environment.

Since I’ll be using floating panes, I turned to Infragistics.  We use their controls in many of our WinForms applications so it seemed logical to use them for my Prism project.  I figured this would be easy since Prism can inject views into any control that hosts an ItemControl or ContentControl

There was a bit of a learning curve to get Infragistics’ Dock Manager to work the way I wanted.  Although I was easily able to place ConentControls in the various dock regions, for some reason I couldn’t get the Dock Manager to fill its parent container.  This behavior wasn’t expected because the WinForms equivalent did fill in the area as expected.  I also followed the Getting Started sample from scratch in a new project and the control didn’t fill…

I did some searching and it looked like others were having the same issue.  The post I found was dated 2009 with no answer so I figured that this issue wasn’t resolved.  I was pretty irate that the expected behavior wasn’t implemented over a year later.  I even went so far as to gripe to the boss about it and asked if I could look at other companies’ components.

After my grumbling session, I took a step back.  Infragistics has been in the controls game a long time (remember Sheridan and VB pre .NET?), they couldn’t have let something like this slip.  I did some more searching and I found that all I needed was a single property: LayoutMode=”FillContainer”

Open hand facing upwards and forcefully place forehead into hand…


Views, ViewModels, And Events

Not all applications have simple UIs.  I have a registered library that handles some of my Region management based on certain requirements.  This manager will inject a View+ViewModel into a Region, nothing complicated here.  In my ViewModel I subscribe to certain events, which again is nothing complicated. 

I noticed something odd when I retrieved data through my application.  Every time I retrieved data, the time it took to display multiplied.  At first, I thought it was because my View wasn’t being properly removed from my Region. Nope, the ActiveView count is 0 as it should be.  I then placed break points in my data layer and found the culprit. 

The expected behavior is that if I request data, a new data layer is instantiated, and my data is returned.  However, every time I requested data, a data layer was instantiated, and the data was returned, but the previously instantiated data layer never got destroyed and was also retrieving data! 

This immediately made me look at the fact that I subscribed to a retrieval event, but never unsubscribed from it.  Prism’s event system must have still had a reference to the CallBack and was still calling it.  This explained the multiplicative time increase.  I ended up having to make sure that my Region manager library unsubscribes from any events when removing Views from my Regions

Thursday, September 23, 2010

VB + C# Adventures (Part 4)

Event Handlers

Adding and removing event handlers in VB is pretty straightforward.  I think the syntax, although wordy, lends itself to readability better than its C# counterpart.  In VB for example:

AddHandler o.SomeEvent, AddressOf Handler
RemoveHandler o.SomeEvent, AddressOf Handler

In C#, you’d have to do the following:

o.SomeEvent += new EventHandler(Handler);
o.SomeEvent -= new EventHandler(Handler);

Now the thing that struck me as “funny” was the need to create a new EventHandler delegate (or whatever event handler delegate you created) to remove it in the C# syntax…


Method Parameters Passed By Reference

Since I’m using methods that pass parameters as reference, you have to use the ref identifier before those parameters in C#.  At first this bugged me because I was so used to not having to do it in VB.  But is it necessarily better not having to identify a reference parameter?  I got to thinking about this and I now think it’s good to have to denote it. 

Why do I think so now?  The intent of a parameter passed by reference is to change the parameter itself (of course this has different implications for value types versus reference types).  This can lead to confusion if you don’t know that the variable that you’re passing in can change.  Requiring the ref identifier alleviates this confusion in my opinion.

Tuesday, September 21, 2010

My Prism Journey (Part 2)

Have you registered some types in your bootstrapper like I have?  Through Prism’s Dependency Injection, I’ve been passing the EventAggregator around to my objects as a parameter.  I’ve also passed in some other registered types, but then I got to thinking…why not just resolve it through the UnityContainer?  Instead of injecting all the registered types I need, I can just pass in a single IUnityContainer and resolve all of the types I need.  Pretty slick!

Monday, September 20, 2010

VB + C# Adventures (Part 3)

I ran into a little hiccup today, which I found amusing.  Parentheses use is very important in C#, whereas in VB you can be lazy about them (think method calls).  In my C# project, I was trying to do an object.ToString.ToUpper, but for some reason Intellisense couldn’t didn’t find ToUpper.  Well, given that ToString is a method call, you need to call it as such: object.ToString().ToUpper().  Has VB made me a lazy developer? :)

Optional parameters… I personally never liked them, but they’re pretty ubiquitous in VB land.  It wasn’t until .NET 4 that C# got this language feature.  VB will let you have optional value and reference parameters, whereas C# won’t let you have optional reference/out parameters.  I’m currently using a data access layer written in VB that has a few methods with optional parameters for my C# project and I saw this first hand through Intellisense.  No brackets were present around the optional reference parameters through C#

Friday, September 17, 2010

My Prism Journey (Part 1)

I’m not going to describe what Prism is because you can just do a search :)  I’m going to post my experiences in trying to leverage the Prism libraries to create a modular application.  The tutorials that come with the library are very helpful so people should definitely read the chm file for help.  I’m also trying to be as MVVM as possible so hopefully I don’t completely mangle my application.

One of the components that I’m adding to my application requires COM Interop… yay.  I did the obligatory aximp call on my ActiveX component, but for some reason I got a file not found exception whenever I tried to access the component at runtime.  Adding the references created by aximp didn’t seem to work.

I had to actually create a new WinForms control library, add the component to my toolbox, drag the component to the control, and then I was able to access the component at runtime.  No worries, I just copied the interop dlls and placed them in a folder so that those can be used instead of the aximp generated ones.

To include interop ActiveX components in your WPF application, you need to host the ActiveX component in a WinForms control.  No problem, add WindowsFormsIntegration so you can use the WindowsFormHost control in your WPF app/control.  You can then add the component to the WindowsFormHost.Child and it will display.  Pretty straight forward…

After getting the above sorted out, I got my interop control to display in the specified region in my shell.  However, it was displaying incorrectly… I set the ActiveX.Dock = Fill, but it wasn’t filling the region.  I sat there for a good hour or so trying to figure this one out… No matter what I did, it just wouldn’t fill the damn region

I then decided to create a little test program to see where the issue could possibly be.  I added a WindowsFormHost and a reference to the ActiveX component.  It filled fine!  Ok, maybe it’s because the region in my application is wrapped with a Tabcontrol.  I wrapped the WindowsFormHost with the TabControl and it still filled correctly.  Wait, to add a region to your shell, you need to specify what the region is hosted in, which is either an ItemsControl or ContentControl

It turns out that I used ItemsControls to host my regions (because the tutorial used those as well).  I then tried switching my region hosts to ContentControls and now my ActiveX component fills as it should… Sheesh.

Thursday, September 16, 2010

VB + C# Adventures (Part 2)

We’re using Visual Studio 2010 so all of my gripes, comparisons, etc will be based on that. 

The biggest thing I noticed right off the bat is in the IDE.  C# Intellisense is kind of clunky compared to its VB counterpart.  I found this kind of weird…

C# Syntax

I’m finding myself using parentheses where I should be using brackets, but it’s rare. 

I miss the With construct that’s in VB.

I sometimes declare my variable name before the type.

Semi-colons…don’t forget those!

Curly-braces galore!

I find the syntax to be a bit more cryptic.


VB Syntax

More verbose, but I find it easier to read (this is just personal preference I guess).

Gotta love direct access to My.Settings and My.Resources.

No need to break after every case in Select (Switch) statements.

Delegate parameters need an AddressOf identifier when passing into a method, whereas C# you just pass in the method.

VB + C# Adventures (Part 1)

I’ll be starting a new series documenting my experiences with using VB and C# simultaneously.  This isn’t meant to be a comparison between the languages, but rather just a non-technical (as can be anyway) dump of the things that are going through my head as I use both languages.  I’m sure this has been done before, but this ought to be fun anyway.

Some personal background…

Back when I was in college, I learned C++ as my first language.  Of course there was some minor SPARC assembly (like I really remember any of that…) and later Java as required by whichever classes I was taking.  I had extremely light exposure to VB6 in my senior year in one of my design classes.  We did UML diagrams and we tied it into a VB skeleton with absolutely no requirement to write any code.  I literally wrote zero lines of VB code in that class.

My first professional job was at a mortgage company and the environment was VB6.  It didn’t take long for me to get adjusted, but I found VB6 a little odd as it went against most of the guiding principles I learned in college as to how to write a program.  Anyway, I’m not going to jump onto the “bash VB” train because that train is full…

Since VB6 was on my resume, my proceeding jobs were also related to me using VB6.  I didn’t mind it, but at the same time I wasn’t really learning anything new… I guess you can say that I started getting bored. 

Fast forward to my current job.  When I first started here, I had zero professional experience with .NET.  I’ve always wanted to get into it, but opportunities seemed slim for me given that I had no professional experience in .NET (catch 22…, but it’s worse for game developers).  I did do some studying on my own in C#, but I wasn’t about to lie and say that I had real-world .NET experience.  I was very fortunate to come across a job listing for my current position and also for the fact that Greg gave me a shot.

Jumping from VB6 to VB.NET wasn’t difficult.  I guess it was because I had retained some of the objected-oriented knowledge from college and the syntax between the two wasn’t too different.  I was (and still am) excited to learn something new for a change.  So far, doing things in C# isn’t too difficult for me.  I had some prior experience with C-style syntax already and I know the .NET framework from doing things in VB.NET already.

I feel that a good carpenter can build a great house with any brand of tools you give them.  The same holds true in the case of a good .NET developer (or any developer for that matter).  A good or bad developer will be a good or bad developer regardless of what language they are using.  This is why I really don’t understand the C# snobbery I see a lot of.  Both languages have their pros and cons, but in the end it’s the result that matters.