Laurent Bugnion (GalaSoft)

Sams Silverlight 2 Unleashed (was: Teach Yourself Silverlight in 24 Hours)

Laurent Bugnion — Mon, 01 Sep 2008 20:20:52 GMT

My editor at Sams (hey Neil :)) and I decided to convert the book I am almost done writing into an Unleashed. There are multiple reasons for that, the most important being that the book addresses multiple audiences, and has a broad range of coverage, which is typical of the Unleashed series. The content goes enough in depth (according to Neil) to be placed in the Unleashed series.

While the Unleashed series usually targets more advanced users than the Teach Yourself one, this book has lots of content that can be useful for a variety of
audiences with chapters that lead the user from the start of their journey through Silverlight. We put a great deal of attention in explaining complex concepts such as Object Oriented Programming, Data Binding, Templates, Transforms, the Animation system, Media integration, and so on with many practical descriptions, hands-on demos and figures which is typical of the books from Sams.

I was not too sure about that move at first, but after thinking about it I am pretty happy about it. Because Silverlight is such a new technology, Silverlight 2 Unleashed will maybe remind you of the famous WPF Unleashed by Adam Nathan, a book that was also published a very short time after WPF was released. And we all know that this book was a great success.

For those of you who already pre-ordered the book at Amazon, you should see the details about the new Unleashed book coming up soon. Sorry about any confusion caused, I am sure the change is for the best and I hope you'll love the book! I just checked the Amazon page and saw that they already updated the picture, but not the title yet, so don't get confused.

Oh, and since Amazon spilled the beans, I can now officially tell you that the book is in color. I won't start again the Petzold vs Nathan debate (sparkled by Jeff Atwood), but let's just say that I am really happy that the book is color coded. I think it makes understanding the code, especially for beginners, easier when it appears just as you see it in Visual Studio.

Preorder my Silverlight book on Amazon

Laurent Bugnion — Mon, 25 Aug 2008 22:24:31 GMT

Wow. That's an incredible feeling, seeing my name on Amazon :) The book is in pre-order!! I'd better get back to editing it then :)

Sams Teach Yourself Silverlight in 24 Hours, Table of Contents

Laurent Bugnion — Thu, 21 Aug 2008 13:38:59 GMT

I've been working since September 2007 (more or less) on an upcoming Silverlight book titled "Teach Yourself Silverlight in 24 Hours" at Sams. This book will be aimed at beginners with the technology (and maybe even beginners in programming). The reader is walked (with a lot of code samples and step-by-step examples) through most features of this amazing technology. The book has 24 chapters, each of them taking more or less (maybe rather a little more than a little less, to be honest :)) one hour to read. There are really tons of demos and cool examples, and so far the feedback I got has been really great.

Clearly, the whole of Silverlight cannot be taught in 24 hours :) but the book should give a very good and deep insight in this framework, and give the reader a taste for more. I also tried to show where additional resources can be found, and to allow the user to continue their education on their own after they finish reading.

Below, you will find the table of content for the first 13 chapters of the book. 13 is my lucky number :) so I think it's a great time to publish this. It's also the chapters I have finished reviewing so far. The rest of the TOC will follow soon, stay posted!

Teach Yourself Silverlight in 24 Hours
Hour 1
Introducing Silverlight
    Where Does Silverlight Come From?
        Automating Web Pages with JavaScript
        Cascading Style Sheets
        Progressing to DHTML
        Communicating in a Richer Way with AJAX
    Using Third-Party Plug-Ins
        Using Java Applets
        Using ActiveX Controls
        Using Flash Applications
    Running on Multiple Platforms
    Making the Web Application Secure
    Introducing Silverlight.net
    What Do I Need to Run Silverlight?
    Updating Your Runtime - Automatically
    Playing with Silverlight Demos
        Playing Chess against Silverlight
        Planning your trips with the “Airline” application
        DeepZooming into the Hard Rock Café
        Finding more demos
    What Do I Need to Develop Silverlight?
        Expression Studio
        Visual Studio 2008
    Reading the Documentation
        Browsing the online reference
        Installing the documentation
        Finding more documentation
        Learning with tutorials
    Looking into Silverlight's Future
        Is ASP.NET/HTML/JavaScript dead?
    About Code in this Book
    Summary
    Workshop
        Quiz
        Answers

Hour 2
Understanding XAML
    Using XML for Data
    Using XML for User Interfaces
    Understanding XML Namespaces
    Defining Additional Namespaces
    Creating a Canvas with Children
    Attaching Properties: Canvas.Left and Canvas.Top
    Documenting Your Markup with XML Comments
    Testing XAML Markup
        Using SilverlightPad
        Using KaXaml
    Setting Properties in XAML
    Changing Brushes
    Composing Scenes in XAML
    Saving Typing, Saving Space
    Summary
    Workshop
        Quiz
        Answers
        Activities

Hour 3
Playing with XAML Transforms and Animations
    Transforming Visuals
    Knowing the Types of Transforms
        RotateTransform
        TranslateTransform
        ScaleTransform
        SkewTransform
        MatrixTransform
    Composing Transforms
    Creating a Basic Animation
    Understanding the Animation's Elements
    Adding a Scale Animation
    Using Other Types of Animations
        Navigating the Property Path
    Deploying the Scene to a Web Page
    Summary
    Workshop
        Quiz
        Answers
        Activities

Hour 4
Expressing Yourself with Expression Blend
    The Expression Studio in Short
    Installing Expression Blend
    Starting Expression Blend
    Setting Options
    Creating a New Project
    Understanding the Panels
    Looking at the Files
    Executing in the Web Browser
    Working with Shapes
    Using the Properties Panel
    Using the Color Picker
        Creating a LinearGradientBrush
        Changing the Gradient Vector
        Creating a RadialGradientBrush
    Creating a 3D Border Effect Using RadialGradientBrush
    Resetting Properties to Their Default Value
    Composing the Elements Hierarchy
    Summary
    Workshop
        Quiz
        Answers
        Activities

Hour 5
Using Media
    Mixing Colors
        Why FF?
    Seeing Through the Transparency Channel
    Seeing Through the Opacity
    Using Vector Graphics
    Adding Media to Your Scenes
        Laying Out the Application
        Adding Pictures
        Adding video
        Testing the Result Quickly in a Web Browser
        Refining the Layout
        Adding Yet Another Image
    Controlling Sound and Video
        Switching Auto-Play Off
        Creating an Endless Loop
        Pausing and Playing the Video
        Setting a "Hand" Cursor
    Checking the Other Properties
        Filling the Space
        Hiding the Media from Mouse Input
    Using Media to Write
        Writing with Video
        Writing with Images
    Transforming Media
    Using Web-Based Media
    Summary
    Workshop
        Quiz
        Answers
        Activities

Hour 6
Blending a Little More
    Creating Transforms
    Creating an OpacityMask
    Paths
        Creating a Path from Scratch
        Using Splines to Modify a Path
        Combining Shapes
    Clipping Path
        Paths in XAML
    Grouping Controls
        Grouping Elements
        Trying Other Panels
        Scrolling the Thumbnails
    Making a User Control
        Creating a User Control
        Using the User Control
    Working on the Thumbnails Gallery
        Adding a Display Frame
        Adding a Reflection under the Thumbnails
        Reflecting Video
        Just One Last Thing
    Summary
    Workshop
        Quiz
        Answers
        Activity

Hour 7
Deploying to a Web Page
    Making Your Own Test Page
    Understanding the object Tag
        Attributes
        Parameters
        Playing with the Attributes and Parameters
        Deploying with JavaScript
    Detecting Silverlight
    Integrating Silverlight in an Existing Web Page
        Understanding the Original Code
        Getting the XAP file
        Modifying the Markup
        Testing the Result
        Referencing a XAP on Another Web Server
    Getting Web Space
        Web Server Requirements
        Finding a Provider
    Getting Started
        Setting Up an FTP Client
        Connecting to Your Server
    Copying Your Silverlight Application
        Testing Your Work
    Summary
    Workshop
        Quiz
        Answers
        Activities

Hour 8
Programming Silverlight with JavaScript
    Learning the Basics
        Comments
        Semicolons
        Case Sensitivity
        Variables
        Functions
        Prototype, this, new
        Types
        Built-In Objects and Libraries
        alert
        undefined
        null
        Handling Events
    Understanding the Concept of Objects
        Interfacing with Other Instances
        Storing Stuff Globally
    Using the Literal Notation and JSON
        Creating Objects with JSON
    Static Members
    Loading Scripts in a Web Page
    Understanding the Context
    Integrating Silverlight in an Existing Web Page Using JavaScript
        Finding Silverlight.js
        Using Silverlight.js
        Detecting Silverlight Versions
        Detecting JavaScript
        Modifying the Web Page During Runtime
    Debugging
    Summary
    Workshop
        Quiz
        Answers
        Activities

Hour 9
Understanding .NET
    Going Back in Time: A Little History of .NET
        Versions, Versions, Versions
        Managed Versus Unmanaged
    Downloading and Installing Visual Studio 2008
    Creating a Silverlight 2 Application in Visual Studio 2008
        Building and Running the Application
        Finding Compilation Errors
        Exploring the Files
        Running the (Empty) Application
    Intellisense
    Programming C# with Basic Constructs
        Types
        Type Conversion
        if then else
        for
        foreach
        while
        do...while
        switch...case
        Operators
    Summary
    Workshop
        Quiz
        Answers

Hour 10
Progressing with .NET
    Programming with Objects in C#
        Breaking Your Problem into Smaller Ones
        Namespaces and the using Directive
        Visibility
        Properties
        Inheritance
    Adding Interactivity to the Thumbnails Application
        Adding Event Handlers in Code
        Displaying the Expanded Media
    Overloading Methods
    Raising Events and Using Delegates
        Creating an EventArgs
        Declaring the Event
        Subscribing to the Event
    Storing Data on the Client
        Understanding the Isolated Storage Security Restrictions
        Creating Objects
        Reading from the Isolated Storage
        Writing to the Isolated Storage
        Updating the User Interface
        Multibrowser Compatibility
    Summary
    Workshop
        Quiz
        Answers
        Activities

Hour 11
Progressing with Animations
    Animating Elements in Blend
        Testing the Application
        Editing the Animations' Properties
        Easing In and Out
    Synchronizing Animations
        Understanding the Animation Elements
    Reversing a Storyboard
    PointAnimation
    Starting and Stopping the Animation
    Working on the Thumbnails Gallery
        Making a Scenario
        Setting the Stage
        Making the Draft Animation
        Easing the Translate Animation
        Triggering the Animation in Code
        Creating the "Fading" Animation in Code
    Summary
    Workshop
        Quiz
        Answers
        Activity

Hour 12
Encoding Videos with Expression Encoder
    Before We Start...
    Introducing Expression Encoder
    Setting Options
    Understanding the Panels
    Importing a Video
    Saving your Changes
    Specifying the Output Type
        Editing the Video Size and Aspect
        Advanced Processing and Codec Settings
        Adding a Leader and Trailer Video
    Testing Before Encoding
    Setting Metadata
        Adding Your Own Metainformation
        Creating Chapters
        Creating Captions
    Encoding the Video for Silverlight
    Checking the Result
        Playing the Video in Full Screen
    Advanced Parameters
    Summary
    Workshop
        Quiz
        Answers
        Activities

Hour 13
Progressing with Videos
    Why Streaming?
    Publishing on Your Own Website
        Copying the Files
    Adding an Overlay
        Adding an Icon or a Video
        Setting Advanced Properties
        Adding a XAML Overlay
    Letting Your Users Choose the Player
        Copying the Files
        Modifying the Files
        Creating the Video
        How Does It Work?
    Publishing on Microsoft Silverlight Streaming Servers
        Signing Up
        Installing, Setting Up the Plug-in, Publishing
        Testing the Output
    Adding the Application in an Existing Web Page
        Using an iframe
        Using JavaScript and a Live Control
    Firing Script Commands (and Catching Them)
    Modifying the Player Template in Blend
        Adding a Full Screen Button
        Handling the Event in Script
        Testing the Result
    Summary
    Workshop
        Quiz
        Answers
        Activities

Joining IdentityMine (and leaving Siemens)

Laurent Bugnion — Wed, 20 Aug 2008 12:08:57 GMT

These last months have been amongst the most intensive I have ever been in my life. Since my last blog post, I have been extremely busy finishing writing my Silverlight book and starting the editing work. It is well underway, and we will publish later this year. It is a very exciting time for me to see that book shaping up after almost a year of work on it. Yes I will be happy to see the finished, paper-printed work!!

Another reason why this time of the year has been especially exciting for me is that I decided to take a new challenge in my professional life. From the 1st of December, I will be working for IdentityMine, the well-known Tacoma- and Seattle-based firm (WA, USA) specializing in Windows Presentation Foundation and Silverlight.

I am really really excited about this opportunity to work with some of the best software developers and designers in this field, such as Robby Ingebretsen, Dr WPF, Nathan Dunlap and more. In the position of Senior Interactive Developer, I will be involved in various projects worldwide and will also help develop the european operations of IdentityMine. In this activity, I will remain based in Zurich, Switzerland, but I expect to continue travelling from time to time. More on this soon!

After 5 weeks holidays in Malaysia and Hong Kong (I really needed a break), I am now back in the office and the news may become official. These next weeks, I will be working hard on ensuring the transition within my current project, and of course finishing the editing work on my book. This will be exciting for sure. Needless to say, I am also bursting with ideas for new projects when the book will be finished, and I am really impatient to start implementing them. I am also looking forward to resuming blogging on a more frequent basis, and you should expect many more articles about Silverlight and WPF soon!! Stay posted.

2 years and 266 posts later...

Laurent Bugnion — Wed, 11 Jun 2008 13:05:21 GMT

2 years ago, on a Sunday, I posted my first blog post. Since then so many amazing things happened, partly due to this blog: I got the MVP status, I got a better recognition in my firm for my expert knowledge on some topics (such as WPF, Silverlight, ASP.NET and C#), I started speaking in conferences... One year later, I got a book deal (more on this soon). I met amazing people, and made a lot of new friends in the industry. I went to Redmond a few times and had the chance to talk to some really amazing talents in the software field. More importantly, I really had the feeling that my contributions were acknowledged, and valued. It's really been 2 amazing years.

To all of you reading these lines, thank you. You make my life as a software engineer better, more interesting, and you really help become a better developer.

Silverlight 2 beta 2 is live!

Laurent Bugnion — Sat, 07 Jun 2008 06:23:40 GMT

Here we go, Silverlight 2 beta 2 can be downloaded and installed! I had the chance to take part to an "insiders" program at Microsoft, and to play with SL2 b2 for a couple of weeks, and it's a good one. You should switch to b2 as soon as you can!

There are obviously incompatibilities between b1 and b2, but much, much less than between the alpha version and b1. We're getting there!!

Silverlight 2 beta 2 will be used to build applications related to the Beijing olympics, so it's going to be a real nature test for that version. As for the final release.... it's still very much hush hush, so let's leave it for now :)

The best place to start is ScottGu's blog. As usual, Scott describes the new features at length, and has links to all the places where you can download the good stuff.

Note that there is also a new version of Blend 2.5 which can be installed next to a "normal" Expression Blend V2. There is supposed to be a new version of Deep Zoom Composer too, but the download seems to be down currently.

Enjoy!!

Microsoft, you're kidding me, right??

Laurent Bugnion — Thu, 05 Jun 2008 17:48:48 GMT

You got to be kidding me. What if I want Expression in the US locale, I can't buy it just because my IP is not in the US? Honestly? You are *that* stupid?

A short break

Laurent Bugnion — Sat, 31 May 2008 11:34:38 GMT

I am going to take a short break of blogging for a couple of months. The reason is simple: I have been working on a book about Silverlight 2 since September last year, and we are in a phase now where I need to concentrate on that exclusively, and put other activities aside. I might post the occasional article from time to time, but until mid-Summer, it's going to be write write write.

Stay posted for news about the book coming up, and don't delete me from your feeds, it's really only temporary :)

My talk at the "Internet Briefing RIA conference" in Zurich

Laurent Bugnion — Thu, 29 May 2008 21:11:28 GMT

I just posted today's talk at the RIA conference in the World Trade Center, Zurich. Unfortunately it was not recorded, but the slides and the demos' source code is available on my site.

The talk went really good, even though the crowd was rather tough :) Trying to "sell" Windows Presentation Foundation, a desktop Windows-only technology, to an audience of web developers, many of them using Java and open source technologies (and even one Adobe employee) sparkled some very interesting discussions. I can't say I convinced everyone (and it was most certainly not my intention), but I think everybody had a really good time. I know for sure that I did!

To all those who stayed until the end of my presentation, and even though mine was the last presentation of the day, thank you very much!! To those who couldn't stay, I hope you'll have fun checking the slides and the demos, and contact me if anything is unclear!!

TweetMyPage V0.2 - Now with "from TweetMyPage" indicator

Laurent Bugnion — Thu, 29 May 2008 09:00:35 GMT

As soon as I had my info page online, I asked Twitter to accept TweetMyPage as a Twitter application, and to mark the messages posted with TweetMyPage with "from TweetMyPage". Note for developers: There is a form to fill on the Twitter API page. It's really fast, and one day later I got the answer that it was accepted.

From now on, messages posted from TweetMyPage are marked as such:

I got a couple of testers so far, and already got a few requests for additional features. I am now evaluating how I can modify the application to integrate these new features, and will update TweetMyPage as soon as I got time (in 2018) (just kidding).

TweetMyPage is in beta for the moment, and if you want to try it, I'll be happy to send you an invite (just leave a comment down here or send me an email. If all goes well, I will make TweetMyPage public next week or so.

GalaSoft "TweetMyPage" released for tests

Laurent Bugnion — Wed, 28 May 2008 19:54:38 GMT

GalaSoft "TweetMyPage" is a web application allowing you to post to Twitter what you're currently reading in your web browser, on a simple button click.

After you install the small "scriptlet" button in your web browser's "bookmarks toolbar" (Firefox) or "Links toolbar" (IE), any time you want to share what you're reading with the world, you can simply click on the "TweetMyPage" button.

If it's the first time in this session that you are posting, you will be asked to enter your Twitter user name and password. After that first time, you will not be asked for it anymore, not until you close your web browser.

As a result, a message will be sent in your name to Twitter, for example:

When you create the "Bookmark button" in the Settings page, you can customize the "Reading" prefix that will be posted, as well as a couple of other settings.

WPF talk this Thursday: "Ultra Rich Interactive Applications"

Laurent Bugnion — Tue, 27 May 2008 12:47:23 GMT

I have been in very much stress lately and hardly had time to post, but I don't forget you, dear readers...

Anyway, this Thursday, I will be talking in a RIA conference organized by the Internet Briefing group here in Zurich, in the World Trade Center. My talk is titled "Ultra Rich Interactive Applications with WPF" and subtitled "When Silverlight is not enough...". I think it's going to be an interesting talk (but obviously I am partial) about the major differences between WPF and Silverlight, and the added richness that WPF provides. I am a big fan of Silverlight, but I have to admit that it's nice going back to the amazing power of WPF sometimes, without having to worry about "is that feature even implemented in Silverlight"?

The talk takes place between 16:30 and 17:30 in the World Trade Center, Leutschenbachstrasse 95, 8050 Zürich. Hoping to see some of you there, maybe!

New GalaSoft stickers

Laurent Bugnion — Thu, 22 May 2008 12:27:10 GMT

On a whim, I made a GalaSoft sticker and ordered 48 of them at CafePress.com. The stickers just arrived yesterday, and they look pretty cool. I plan to keep some on me, so next time you cross my path, make sure you get a GalaSoft sticker for your laptop

My resume is now online

Laurent Bugnion — Fri, 09 May 2008 22:28:08 GMT

I finally did something I wanted to do for a loooooong time: I cleaned up and put my resume online on my website. Note for Beat (my boss), if you read this, don't panic, I am not leaving just right now :) Anyway. For those of you who like to know my (professional) self better, feel free to take a look. If you want a username and password to check my certificates and awards, contact me. And if you have any comment, give me feedback!!

WPF: ListView/GridView minimum and maximum width for a column

Laurent Bugnion — Tue, 06 May 2008 17:05:12 GMT

A WPF ListView is a possible replacement for a datagrid, when it doesn't have to support advanced features like grouping or filtering of rows. If you use a ListView in your WPF application, and set the "View" property of this ListView to be a GridView.

A ListView/GridView even supports features like reordering and resizing columns. Unfortunately, it is not possible to define a minimum or maximum width for the columns. Fortunately, it is not really to do this in the code behind. Let's see how.

First we need to understand how exactly the resizing of a GridView column works. When a column can be resized, a narrow vertical line appears on the right side of the column. Passing the mouse over this line turns the cursor into a "resize" cursor.

To find out what exactly this line is made of, we can use a tool like Snoop, or Mole. These tools display the inner structure of a WPF UI, also known as the Visual Tree. For example, in Mole, we can navigate down to our ListView and display the header row's inner structure:

The feature that is of particular interest to us is the "Thumb" control, named PART_HeaderGripper. This requires some explanations:

A Drag action is the action through which a control is selected (click-and-hold) and then the mouse is moved. The expected action is usually that the clicked control moves together with the mouse, but other actions may be performed too, for example resizing the columns of a grid, etc...
A Thumb is a small WPF control that can be dragged. It has a collection of events that are used to program what happens when a drag action is performed on the control. For example, the event Thumb.DragDeltaEvent is fired every time that the Thumb is dragged a little.
Note: A Thumb doesn't really look like anything (well, it does look like a Rectangle!). With the great ability that WPF has to redefine the look&feel of any control, you can make a Thumb look like anything you need. This is why the Thumb control is in the namespace System.Windows.Controls.Primitives: The Thumb is usually used to create other controls, hence the "Primitives".
The makers of WPF controls have for convention to name inner controls of other controls with the "PART_" prefix.

Once we know this, we can try to intercept the events raised by the Thumb control named "PART_HeaderGripper", when the ListView's user resizes the columns. Remember, in WPF, events are "routed", we say that they "bubble" up from the control they originate from to the parent and the parent's parent, etc...

As a first try, we can add an event handler on the ListView and try to handle the "Thumb.DragDelta" event:

<ListView x:Name="MyListView"
          IsSynchronizedWithCurrentItem="True"
          ItemsSource="{Binding Path=Items,
                                Mode=Default,
                                Source={StaticResource DataProvider}}"
          Thumb.DragDelta="Thumb_DragDelta">

with:

void Thumb_DragDelta(object sender, DragDeltaEventArgs e)
{
  // Do nothing for the moment
  Console.WriteLine("Thumb_DragDelta");
}

Unfortunately, if we place a breakpoint inside the Thumb_DragDelta event handler, it is never reached, not even if you resize any column of the ListView. Why not? Well, when a routed event is handled by any control, it can be marked as "handled". This is done by setting the RoutedEventArgs.Handled property to true inside the event handler.

Fortunately, there is a way to tell the framework that we are interested in an event even if it has been marked as handled. We cannot do this in XAML, however, so just remove the Thumb.DragDelta from the XAML:

<ListView x:Name="MyListView"
          IsSynchronizedWithCurrentItem="True"
          ItemsSource="{Binding Path=Items,
                                Mode=Default,
                                Source={StaticResource DataProvider}}">

Instead, we will add an event handler in code behind. This is one of the few things that you cannot do in XAML!

public Window1()
{
  InitializeComponent();

  MyListView.AddHandler(Thumb.DragDeltaEvent,
    new DragDeltaEventHandler(Thumb_DragDelta),
    true);
}

Notice that the last parameter of the AddHandler override is set to "true": This is what indicates that we want to get notified when the DragDelta event "bubbles" to us, even if it has been marked handled before it reaches us. This time, if you run the application and resize a column, the event handler is executed and the breakpoint is reached.

The last thing we need to do is to forbid the column to be resized under a minimum size, or above a maximum size. To do this, we need to do a few steps:

Get the Thumb at the origin of the event. This is not the "sender" parameter, because the event handler is placed on the ListView. So even though the routed event originates on the Thumb, the "sender" is actually the ListView. However, there is another way to get the Thumb: The parameter "e" (of type DragDeltaEventArgs), like all RoutedEventArgs, contains a property named "OriginalSource". This is the Thumb we want!
Then, we want to get the GridViewColumnHeader containing the Thumb. Here too, we need to understand how the visual tree is built. All controls in WPF are essentially lookless, and the look&feel is created in a ControlTemplate, which is separate. We can, however, get the parent's template using the TemplatedParent property.
We're almost there: Once we have the GridViewColumnHeader, all we need to do is get the Column it belongs to (conveniently exposed in the Column property), and set its Width to the minimum respectively maximum value we want to use. Translated in code, this is:

void Thumb_DragDelta(object sender, DragDeltaEventArgs e)
{
  Thumb senderAsThumb = e.OriginalSource as Thumb;
  GridViewColumnHeader header
    = senderAsThumb.TemplatedParent as GridViewColumnHeader;
  if (header.Column.ActualWidth < MIN_WIDTH)
  {
    header.Column.Width = MIN_WIDTH;
  }
  if (header.Column.ActualWidth > MAX_WIDTH)
  {
    header.Column.Width = MAX_WIDTH;
  }
}

where MIN_WIDTH and MAX_WIDTH are two constants. We could as well use properties to be able to set these values from the outside.

With this code, the column will be resizable up to a certain limit, and then the Thumb will stop moving. While it requires a good understanding of the inner works of a WPF control, this is not very complicated. It requires some code-behind, however, and cannot be done in pure XAML.