Joe's Blog

New Blog

Joe — Fri, 15 Jan 2010 07:05:00 GMT

After many months of ignoring my blog, I finally decided to try and get it fixed. After the last Community Server upgrade something in the software was broken, and I was unable to use Windows Live Writer to blog. The upgrade was such a headache I loathed even the thought of spending more time trying to figure out the issue. This week I finally decided to break down and figure it out. However it appears to be too little too late. Being unable to find the required upgrades on their website, I contacted »telligentsystems tech support. This is what I received:

“Unfortunately, we no longer offer the free versions of our products, nor do we support them any longer. We will not be able to provide you the upgrades. Please contact our sales department if you wish to purchase a license.”

So, welcome to WordPress! I was pleasantly surprised with a simple and seamless install. After browsing through some of the available themes, I finally decided to create my own. I created this theme based on Bea Stollnitz’s wonderful looking blog. My goal is to eventually move my posts over, however for now my old blog will still be up and running. For now, lets create some new XAML posts!

Building a Databound WPF Menu Using a HierarchicalDataTemplate

Joe — Wed, 26 Nov 2008 01:49:00 GMT

I had a colleague ask me how he could solve a databinding problem while building a WPF Menu. The immediate answer wasn’t apparent to me, though it’s actually quite simple. A while back Karl Shifflett wrote up an excellent example of doing something similar. I take his example one step further by showing how you can easily bind properties to the MenuItem instead of assigning one-time values.

Download Source: WPFDataBoundMenu.zip

We’re going to use a simple Business Object which represents our MenuItem. It has four properties: MenuText, IsEnabled, Command, and Children.

public class MyBusinessObject : INotifyPropertyChanged

    private bool _isEnabled;

    private string _menuText;

    private ICommand _command;

    private ObservableCollection<MyBusinessObject> _children;

    public event PropertyChangedEventHandler PropertyChanged;

    public MyBusinessObject()

        Children = new ObservableCollection<MyBusinessObject>();

    public string MenuText

        get { return _menuText; }

set

            _menuText = value;

            RaisePropertyChanged("MenuText");

    public bool IsEnabled

        get { return _isEnabled; }

set

            _isEnabled = value;

            RaisePropertyChanged("IsEnabled");

    public ICommand Command

        get { return _command; }

set

            _command = value;

            RaisePropertyChanged("Command");

    public ObservableCollection<MyBusinessObject> Children

        get { return _children; }

set

            _children = value;

    private void RaisePropertyChanged(string propertyName)

        var handler = PropertyChanged;

        if (handler != null)

            handler(this, new PropertyChangedEventArgs(propertyName));

We’ll build our window to include a Menu and a Button. When we click the button we want to toggle the IsEnabled property of one of our Business Objects.

<Window

    x:Class="WpfApplication1.Window1"

    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

    xmlns:local="clr-namespace:WpfApplication1"

    Title="Window1"

    Height="400"

    Width="700">

    <Window.Resources>

        <HierarchicalDataTemplate

            DataType="{x:Type local:MyBusinessObject}"

            ItemsSource="{Binding Path=Children}">

            <ContentPresenter

                Content="{Binding MenuText}"

                Loaded="ContentPresenter_Loaded"

                RecognizesAccessKey="True" />

        </HierarchicalDataTemplate>

    </Window.Resources>

    <Grid

        Margin="10">

        <Grid.RowDefinitions>

            <RowDefinition Height="Auto" />

            <RowDefinition Height="Auto" />

        </Grid.RowDefinitions>

        <Menu

            ItemsSource="{Binding}"/>

        <StackPanel

            Grid.Row="1">

            <Button

                Content="Toggle Enable"

                Click="Enable_Click"/>

        </StackPanel>

    </Grid>

</Window>

In our code-behind for the window we build a collection of MyBusinessObject’s. We then assign that collection to the DataContext of our Window. This allows the Menu control to bind its ItemsSource to the current value of the DataContext (ItemsSource="{Binding}"). Where we do the magic is in the ContenPresenter_Loaded event handler. This is fired when the MenuItems are being built. Inside the handler we get a reference to the ContenPresenter then walk up the tree to it’s Parent MenuItem. UtilityMethods.FindParent accomplishes this task by using the VisualTreeHelper and recursively walking the tree. We then can get a reference to our MyBusinessObject through the DataContext of the MenuItem. This allows us to build bindings, in code, to bind to various properties. It’s important to remember that we can do lots of the same things in code in which we can do in XAML. XAML is just usually funner. =]

public partial class Window1 : Window

    private ObservableCollection<MyBusinessObject> _options;

    public Window1()

        InitializeComponent();

        _options = new ObservableCollection<MyBusinessObject>();

        // build simple menu structure

        MyBusinessObject menuTwo = new MyBusinessObject

            MenuText = "Two",

};

        menuTwo.Children.Add(

            new MyBusinessObject

                MenuText = "Child 1"

);

        menuTwo.Children.Add(

            new MyBusinessObject

                MenuText = "Child 2",

                IsEnabled = false

);

        _options.Add(

            new MyBusinessObject

                MenuText = "One"

);

        _options.Add(menuTwo);

        DataContext = _options;

    private void ContentPresenter_Loaded(object sender, RoutedEventArgs e)

        // get the content presenter

        ContentPresenter contentPresenter =

            sender as ContentPresenter;

        // get reference to menu item

        MenuItem menuItem =

            UtilityMethods.FindParent<MenuItem>(contentPresenter);

        // get reference to business object

        MyBusinessObject myBusinessObject =

            menuItem.DataContext as MyBusinessObject;

        // create bindings

        Binding isEnabledBinding = new Binding("IsEnabled");

        isEnabledBinding.Mode = BindingMode.TwoWay;

        isEnabledBinding.Source = myBusinessObject;

        menuItem.SetBinding(MenuItem.IsEnabledProperty, isEnabledBinding);

        Binding commandBinding = new Binding("Command");

        commandBinding.Mode = BindingMode.TwoWay;

        commandBinding.Source = myBusinessObject;

        menuItem.SetBinding(MenuItem.CommandProperty, commandBinding);

    private void Enable_Click(object sender, RoutedEventArgs e)

        // toggle IsEnabled

        _options[1].Children[1].IsEnabled =

            !_options[1].Children[1].IsEnabled;

And that’s it! I hope that helps!

Download Source: WPFDataBoundMenu.zip

Joe

UI Design Patterns Presentation Code + Slide Deck

Joe — Fri, 14 Nov 2008 07:24:00 GMT

Thank you to everyone who came to my presentation on UI Design patterns! It was great to see so many people interested in patterns for building user interfaces.

One user group member recorded the presentation on his laptop's webcam; I should have that available for download this weekend. The video is so-so, but the audio isn't too bad. Thanks Walt!

Links

Download Code & Slides - http://xamlcoder.com/joe/downloads/UIDesignPatterns2008.zip

Martin Fowler MVC
Martin Fowler MVP
ASP.NET MVP & Other Patterns
Karl Shifflett MVVM

Requirements

Visual Studio 2008 SP1
Silverlight Tools for Visual Studio
NUnit (included with code)
Rhino Mocks (included with code

There's a small "gotcha" with the Silverlight sample. The implemenation is slightly different than that of it's WPF counterpart. Silverlight Dependency properties do not automatically fire change notifications when their values have changed. Therefore if you want property change notifications your control (read DependencyObject which the Dependency Property is a member of) itself has to implement the INotifyPropertyChanged interface, or you can do what I've done here and set the DataContext of a container control.

Utah .NET User Group Presentation - UI Design Patterns

Joe — Mon, 10 Nov 2008 21:39:00 GMT

Join me this week at the Utah .NET User Group where I’ll be giving a presentation on UI Design Patterns.

UI Design Patterns

In this session we’ll explore three UI design patterns: Model View Controller (MVC), Model View Presenter (MVP), and Model View ViewModel (MVVM). We’ll prove that you can reuse the same logic to drive a WinForms, ASP.NET, WPF, or Silverlight "View". We’ll also see how using these patterns allow the bulk of your UI to be testable using testing frameworks such as NUnit and Rhino Mocks.

Date: Thursday, November 13th, 2008

Time: 6:00 PM

Place: Neumont University 3rd Floor (10701 South River Front Parkway, South Jordan)

See you there!

Building composite Applications Using PRISM Presentation

Joe — Mon, 03 Nov 2008 23:57:00 GMT

Thank you to everyone who attended my presentation on PRISM at the Utah Code Camp this past weekend. Here’s a link to my sample code and slide deck.

http://xamlcoder.com/joe/downloads/PRISM-UTCodeCamp2008.zip

Note that you’ll need VS2008 SP1 with the Silverlight Tools for Visual Studio 2008 SP1 installed to run the Silverlight demo.

Composite Silverlight 2.0 Application Library Updated to RTW

Joe — Tue, 21 Oct 2008 20:46:00 GMT

I’ve updated my demo of the Composite Silverlight Library I built to work with Silverlight RTW. The P&P group has plans to ship the next version of the PRISM library (PRISM 2.0) that supports Silverlight, so I’ve started to use their bits instead of the ones that I built with this sample. Bellow is a screenshot of the conversion. As you can see, the default styles in Silverlight 2.0 have been changed, and the rendering is much better.

Download: CompositeSilverlightRTW.zip