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 Monday, March 24, 2008

Dunn Training is holding a three day CSLA .NET training class in Toronto, May 5-7. Dunn's three day class is a great way to jumpstart your use of CSLA .NET, and Toronto is a fun city, so this is a great opportunity!

For details go to http://www.dunntraining.com/training/schedule.htm.
Monday, March 24, 2008 8:50:29 PM (Central Standard Time, UTC-06:00)  #    Disclaimer  |  Comments [0]  | 
 Monday, March 17, 2008

n579576978_702761_9418Microsoft Tech Ed 2008 is coming up in early June. This year they are splitting it into two parts: IT Pro and Developer, each of which gets a week. I think this is a good move, as it allows the Developer week to be focused on topics developers care about. They've done this for a couple years now in Europe and it has been successful there.

The developer week is June 3-6.

I'm a co-chair for the Developer Tools track, which covers Visual Studio, all the languages and related topics. I think we put together a great set of speakers and topics in this track, so I'm very excited about it!

I'm also one of the featured speakers, and you can see details about all the featured speakers in a nice little Silverlight app.

Monday, March 17, 2008 7:26:55 AM (Central Standard Time, UTC-06:00)  #    Disclaimer  |  Comments [0]  | 
 Sunday, March 16, 2008

I recently participated in a webcast covering SOA, REST and various related topics. You can listen to it here

http://www.slickthought.net/post/Minneapolis-Developer-Roundtable-Podcast---Talking-REST.aspx

Sunday, March 16, 2008 6:32:37 PM (Central Standard Time, UTC-06:00)  #    Disclaimer  |  Comments [0]  | 

I have a question (helping a colleague do some research) for all .NET VB developers.

Do you use late binding in VB? If so, how/why do you use it? What are the scenarios where you find it of value?

I'll start this off with my own observations:

I use late binding when getting data of a given shape from unknown types.

For example, you can write a nice bit of reusable data access code that accepts data from a web service, LINQ object, etc. by using late binding. You can’t easily do this without late binding in fact, because the types of the objects are different even though their shapes are the same.

That dynamic interface concept that got dropped from VB9 would address this issue in a better way, but late binding makes it work too.

I also use late binding when creating some generic types. There are cases where generics and casting are problematic, but converting a value to type Object first allows you to do a cast or operation that wouldn’t otherwise be allowed. I don’t know if this is “late binding” as such, but it is a useful technique!

I have used late binding when dynamically loading an assembly for interaction. Ideally you’d require the assembly author to implement one of your interfaces, but that’s not always possible, and late binding is a particularly nice way to get “polymorphic” access to multiple assemblies that you don’t control.

What about you?

Sunday, March 16, 2008 2:56:16 PM (Central Standard Time, UTC-06:00)  #    Disclaimer  |  Comments [0]  | 
 Friday, March 14, 2008

Sometimes you just can't catch a break...

About two weeks ago my server's motherboard went bad. That's no fun, but www.lhotka.net is running in a virtual machine (VM) on Virtual Server, so it was relatively easy to get it back running on my desktop workstation. Not ideal, but a temporary workaround. And since I was heading to Las Vegas for MIX 08 I didn't need the desktop anyway.

Last weekend my good friend (and hardware guru) Rick came over and we confirmed it was the motherboard, and purchased replacement parts. A shiny new Q6600 CPU and a motherboard to match. Now my physical server is a quad core machine, and that's very cool. Though I am running Windows Server 2003 64 bit and Virtual Server 2005 R2 as the host, so the VM still can't use more than one CPU :(  Still, each core of the new CPU is much faster than the previous single-core CPU.

On Monday I got the VM copied off my desktop and onto the new server. All seemed to be working, which made me happy. And I blissfully flew off to LA to spend the week with a client.

Only to find out that there's a problem! The VM uses a virtual network adapter that is attached to the host's real network adapter. For some reason the VM periodically sees the network adapter become "unplugged". Which of course it is not. The physical NIC is working fine, but the VM is losing it. Manually disabling/enabling the virtual NIC fixes the problem, but this happens every few hours (so if you've noticed www.lhotka.net offline a lot the past few days this is why).

Also, my System event log was (and is) filling up with "The netcard driver failed the query for OID_GEN_LINK_SPEED", related to the QoS service.

Googling turned up a few people who've had the same problem. But no serious answers. Apparently people solved the problem but never posted their solution in any coherent manner. More googling, and then more... Eventually I found some tidbits of info here and there. Things to try:

  1. Disable the QoS service on the virtual NIC (had no effect for the original poster or me - though it does stop the event log entries)
  2. Remove the virtual NIC and restart the VM so it redetects the NIC (didn't work for the original poster, nor for me)
  3. On the host, uncheck the virtual server support on the real NIC, reboot the host, re-check the virtual server support on the real NIC, reboot the host (I don't know if it helped the original poster, but it didn't help me)
  4. I noticed that the host didn't have the Windows Firewall turned on, so today I turned it on (I don't know yet if that had any impact, but I feel better having done it)
  5. Uninstall Virtual Server, then reinstall it (don't know if it worked for the original poster, and haven't tried this yet)

Interestingly enough, enabling the firewall on the host might have had an impact. The VM has been successfully running for around 5 hours now. I am rather doubtful that this is the problem, but maybe I'll get lucky. I still can't enable the QoS service without flooding the event log with errors though...

To add insult to injury, as I was messing with all this today (running on 3 hours of sleep and having just flown back from LA), some spammer decided to target my wife's blog for pingback spam. It is like a denial of service attack - they are sending 4-5 post requests to her blog every second. And dasBlog is clearly not capable of handling that kind of volume. So the VM pegs at 100% CPU, the disk is thrashing, everything is incredibly slow, and they somehow got past the fact that she has pingbacks turned off and managed to load hundreds of them into her blog...

The dasBlog cleaner utility got rid of about 70% of them, and I wrote a quick VB app to clean the rest (the LINQ to XML support in VB is so incredibly awesome!!!), and we tweaked some more settings so I don't think they can get the pingbacks to record anymore. But they are still trying, so now it really is a DOS attack.

Do I think spammers should go to prison? Absolutely. They cause direct, tangible harm, and they should be deprived of their ability to harm or interact with normal human beings if at all possible. They are like mass muggers.

What puzzles me is that the URLs they were spamming into the blog don't actually go anywhere. Each one was unique and semi-random. I can't figure out the motivation behind this, since they clearly can't get any value out of a URL that doesn't go anywhere can they?

So maybe they shouldn't to prison. Maybe they should be locked up in a looney bin somewhere?

Anyway, I very much doubt this is the end of the saga. Though I think I've blocked the pingbacks, they continue to pound the server. And I expect the server's NIC to disconnect any time now - in which case I'll try the uninstall/reinstall of Virtual Server in the hope that solves the problem...

I really, really hate computers sometimes...

Friday, March 14, 2008 6:35:51 PM (Central Standard Time, UTC-06:00)  #    Disclaimer  |  Comments [0]  | 
 Monday, March 10, 2008

In a previous post I talked about the new property declaration syntax options in CSLA .NET 3.5. When it comes to child objects, if the shortest form is used then CSLA will pretty much completely take care of all parent-child object interaction so you don't have to do it by hand. This is a tremendous code savings!

So declaring a child property like this:

private static PropertyInfo<ChildList> ChildListProperty =
  RegisterProperty<ChildList>(new PropertyInfo<ChildList>("ChildList");
public ChildList ChildList
{
  get { return GetProperty<ChildList>(ChildListProperty); }
}

allows CSLA to manage the child object. Of course you do need to create the child object somewhere, such as in the DataPortal_XYZ methods:

[RunLocal]
private void DataPortal_Create()
{
  // initialize other fields here
  LoadProperty<ChildList>(ChildListProperty, ChildList.NewList());
  base.DataPortal_Create();
}

private void DataPortal_Fetch(...)
{
  // initialize other fields here
  LoadProperty<ChildList>(ChildListProperty, ChildList.GetList(this.Id));
}

Another option is to use a lazy loading scheme. There are a couple options in how you can use lazy loading. You can avoid the DataPortal_Create() implementation by just creating a new, empty list - and I do this almost all the time now:

private static PropertyInfo<ChildList> ChildListProperty =
  RegisterProperty<ChildList>(new PropertyInfo<ChildList>("ChildList");
public ChildList ChildList
{
  get
  {
    if (!FieldManager.FieldExists(ChildListProperty))
      SetProperty<ChildList>(ChildListProperty, ChildList.NewList());
    return GetProperty<ChildList>(ChildListProperty);
  }
}

With this approach you still need to load the child data in the DataPortal_Fetch() method. The only thing this does is eliminate the need for the code in DataPortal_Create() - which often means you don't need DataPortal_Create() at all.

Another option is to truly lazy load the object by calling a factory method that actually loads the object with existing data:

private static PropertyInfo<ChildList> ChildListProperty =
  RegisterProperty<ChildList>(new PropertyInfo<ChildList>("ChildList");
public ChildList ChildList
{
  get
  {
    if (!FieldManager.FieldExists(ChildListProperty))
      SetProperty<ChildList>(ChildListProperty, ChildList.GetList(this.Id));
    return GetProperty<ChildList>(ChildListProperty);
  }
}

Obviously this requires that the ChildList class implement a GetList() factory that calls the data portal so it can be loaded independently from its parent. This is different from the first example, where GetList() would use the new child data portal support (or could be implemented the old 3.0 way). I'll discuss the new child data portal support in a future blog post.

If you use lazy loading, CSLA will automatically ensure that the newly created child has its edit level set correctly and that all data binding events cascade appropriately.

in all cases you no longer need to write code in a parent object like this:

protected override bool IsDirty
{
  get
  {
    return base.IsDirty || _childList.IsDirty;
  }
}

protected override bool IsValid
{
  get
  {
    return base.IsValid && _childList.IsValid;
  }
}

Nor do you need to do any hooking of child object events like PropertyChanged or ListChanged - that's all automatic as well.

Monday, March 10, 2008 10:15:41 PM (Central Standard Time, UTC-06:00)  #    Disclaimer  |  Comments [0]  | 
 Sunday, March 09, 2008

I'm just back from the MIX 08 conference. This was the first conference I've attended in many years (around 10 I think) where I wasn't speaking or somehow working. I'd forgotten just how fun and inspiring it can be to simply attend sessions and network with people in the open areas. No wonder people come to conference!! :)

Not that it was all fun and games. I did have meetings with some key Microsoft people and Scott Hanselman interviewed me for an upcoming episode of Hanselminutes (discussing the various data access and ORM technologies and how they relate to CSLA .NET 3.5).

The Day 1 keynote was everything I'd hoped for.

Well, nearly. The first part of the keynote was Ray Ozzie trying to convey how Microsoft and the web got to where it is now. The goal was to show the vision they are pursuing now and into the future, but I thought the whole segment was rather flat.

But then Scott Guthrie came on stage and that was everything you could hope for. Scott is a great guy, and his dedication and openness seem unparalleled within Microsoft. I remember first meeting him when ASP.NET was being unveiled. At that time he seemed so young and enthusiastic, and he was basically just this kick-ass dev who'd created the core of something that ultimately changed the Microsoft world. Today he seems nearly as young and easily as enthusiastic, and he's overseeing most of the cool technologies that continue to change the Microsoft world. Awesome!

So ScottGu gets on stage and orchestrates a keynote that really illustrates the future of the web. Silverlight (which makes me SOOoooo happy!), IE8, new data access technologies (like we needed more, but they are still cool!) and things like ASP.NET MVC and more.

As I expected, they released a whole lot of beta code. You can get a full list with links from Tim Sneath's blog. He also has links to some getting started materials.

The real reason for keynotes though, is to inspire. And this keynote didn't disappoint. The demos of Silverlight and related technologies were awesome! There was some funny and cute banter with the casting director from Circ del Sole as she demonstrated using a cool disconnected WPF app. There was a fellow RD, Scott Stanfield, showing integration of SeaDragon into Silveright so we can look (in exquisite detail) at the memorabilia owned by the Hard Rock Cafe company, some thought-provoking demos of Silverlight on mobile devices and more.

Now to be honest, I've never been a fan of the web development model. Having done terminal-based programming for many years before coming to Windows, I find it hard to get excited about returning to that ancient programming model. Well, a worse one actually, because at least the mainframe/minicomputer world had decent state management...

AJAX helps, but the browser makes for a pretty lame programming platform. It is more comparable perhaps to an Apple II or a Commodore 64 than to a modern environment, and that's before you get into the inconsistencies across browsers and that whole mess. Yuck!

Which is why Silverlight is so darn cool! Silverlight 2.0 is really a way to do smart client development with a true web deployment model. Much of the power of .NET and WPF/XAML, with the transparent deployment and cross-platform capabilities of the browser world. THIS is impressive stuff. To me Silverlight represents the real future of the web.

It should come as no surprise then, that I spent my time in Silverlight 2.0 sessions after the keynote. Sure, I've been working (on and off) with Silverlight 1.1/2.0 for the past several months, but it was a lot of fun to see presentations by great speakers like Joe Stegman (a Microsoft PM) and various other people.

One of the best sessions was on game development with Silverlight. I dabble in game development whenever I have spare time (not nearly as much as I'd like), and so the talk was interesting from that perspective. But many of the concepts and techniques they used in their games are things designers and developers will likely use in many other types of application. Background loading of assemblies and content while the app is running, and some clever animation techniques using pure XAML-based concepts (as opposed to some other animation techniques I saw that use custom controls written in C#/VB - which isn't bad, but it was fun to see the pure-XAML approaches).

Many people have asked about "CSLA Light", my planned version of CSLA .NET for Silverlight. Now that we have a Beta 1 of Silverlight I'll be working on a public release of CSLA Light, based on CSLA .NET 3.5. Microsoft has put a lot more functionality into Silverlight 2.0 than they'd originally planned - things like data binding, reflection and other key concepts are directly supported. This means that the majority of CSLA can be ported (with some work) into Silverlight. The data portal is the one big sticking point, and I'm sure that'll be the topic of future blog posts.

My goal is to support the CSLA .NET 3.5 syntax for property declaration and other coding constructs such that with little or no change you can take a business class from full CSLA and have it work in CSLA Light. This goal excludes the DataPortal_XZY implementations - those will almost always be different, though if you plan ahead and use a DTO-based data access model even that code may be the same. Of course time will tell how closely I'll meet this goal - but given my work with pre-beta Silverlight 2.0 code I think it is pretty realistic.

Scott Guthrie indicated that Silverlight 2.0 Beta 1 has a non-commercial go-live license - right now. And that Beta 2 would be in Q2 (I'm guessing June) and would have a commercial go-live license, meaning it can be used for real work in any context.

The future of the web is Silverlight, and Beta 1 is the start of that future. 2008 is going to be a great year!

Sunday, March 09, 2008 5:18:27 AM (Central Standard Time, UTC-06:00)  #    Disclaimer  |  Comments [0]  | 
 Monday, March 03, 2008

I am one of the Microsoft Regional Directors, which means that I'm in a group containing some of the most thoughtful (and sometimes challenging :) ) people in the Microsoft community. That's a humbling place to be, especially when we all get together and talk about the current and future state of technology!

The RD program has a web site, www.TheRegion.com, which includes an aggregated blog summary of all the RD bloggers. Not all RD's blog, but quite a few of us do, and the topics run the entire range from gadgets to hardware to networking to software development to architecture. In short, www.TheRegion.com is a treasure trove of great information!

Monday, March 03, 2008 5:32:43 PM (Central Standard Time, UTC-06:00)  #    Disclaimer  |  Comments [0]  | 

Another place where I was able to reduce business object code in CSLA .NET 3.5 was to effectively eliminate the GetIdValue() method.

Prior to version 3.5, GetIdValue() was required, and you had to provide a unique value identifying your object. This value was used to implement Equals() and GetHashCode(), and was used as the ToString() value. This was good, because it enabled the concept of logical equality, where objects were equal to each other based on their id value.

For better or worse, WPF doesn't support logical equality. They only support absolute equality - ideally implemented by comparing all properties of the two objects so two objects are only equal if all their properties are equal. A poor man's replacement is to use reference equality - which is much faster but is technically less accurate. The effective default in .NET is reference equality.

CSLA .NET 3.5 no longer overrides Equals() or GetHashCode(), so it now uses the .NET default behavior. This makes WPF happy. This might break some people's existing code (though a poll on the forum indicates it is a non-issue for virtually everyone), because there is no longer any idea of logical equality unless you implement it yourself.

The upside though, is that you no longer need to override GetIdValue(). I left the method in the framework for backward compatibilty, so if you do override it your code will continue to compile (though the value is now only used in a ToString() override).

Monday, March 03, 2008 8:53:36 AM (Central Standard Time, UTC-06:00)  #    Disclaimer  |  Comments [0]  | 
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