Azure, C# and Everything .Net: July 2010

How do you adapt a pre-existing Object Model (that doesn’t support notifications)?
How do I extend my ViewModel with a commanding infrastructure?
How do I make my standard .Net resource available as part of ViewModel Metamodel?
How do I make my model support a State Machine?
- This is could be really useful when to trigger actions based on object state
- Essentially, we’re moving all action(s)/behaviors into commands making the models passive
How do I extend the existing Model with new properties?
How do I create a brand new model from scratch (fully dynamic)?
How do I make related information part of Model MetaModel?
- For example, EmployeeKind can be an enum of ‘Skilled, Unskilled, Others’.
How do I emulate standard static C# property on a Dynamic model?
How do I add support for Radio / Linked Properties
How do I translate an existing object into a dynamic Model?
How do I translate the same back?

I came across an interesting problem recently: How do you assign AutomationIds automatically for Items in an ItemsControl?

<UserControl

    x:Class="ThinkFarAhead.AutoAutomationId.MainPage"

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

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

    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"

    xmlns:local="clr-namespace:ThinkFarAhead.AutoAutomationId"

    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"

    mc:Ignorable="d" d:DesignHeight="300" d:DesignWidth="400">

  <Grid x:Name="LayoutRoot" Background="White">

    <StackPanel>

      <ItemsControl x:Name="ItemsControl">

        <ItemsControl.ItemTemplate>

          <DataTemplate>

            <TextBlock

                local:AutomationHelper.Parent=

                    "{Binding ElementName=ItemsControl}"

                local:AutomationHelper.CurrentItem=

                    "{Binding Path=DataContext,

                    RelativeSource={RelativeSource TemplatedParent}}"

                local:AutomationHelper.IndexedId="Message{0}"

                    AutomationProperties.AutomationId=

                        "{Binding (local:AutomationHelper.IndexedId),

                        RelativeSource={RelativeSource Self}}"

                Text="{Binding (AutomationProperties.AutomationId),

                    RelativeSource={RelativeSource Self}}" />

          </DataTemplate>

        </ItemsControl.ItemTemplate>

      </ItemsControl>

    </StackPanel>

  </Grid>

</UserControl>

namespace ThinkFarAhead.AutoAutomationId

    using System.Windows;

    using System.Windows.Controls;

    public static class AutomationHelper

        #region Constants and Fields

        public static DependencyProperty CurrentItemProperty =

            DependencyProperty.RegisterAttached(

                "CurrentItem",

                typeof(object),

                typeof(AutomationHelper),

                new PropertyMetadata(null)

);

        public static DependencyProperty IndexedIdProperty =

            DependencyProperty.RegisterAttached(

                "IndexedId",

                typeof(string),

                typeof(AutomationHelper),

                new PropertyMetadata(null)

);

        public static DependencyProperty ParentProperty =

            DependencyProperty.RegisterAttached(

                "Parent",

                typeof(ItemsControl),

                typeof(AutomationHelper),

                new PropertyMetadata(null)

);

        #endregion

        #region Public Methods

        public static object GetCurrentItem(DependencyObject element)

            return element.GetValue(CurrentItemProperty);

        public static string GetIndexedId(DependencyObject element)

            return element.GetValue(IndexedIdProperty) as string;

        public static ItemsControl GetParent(DependencyObject element)

            return element.GetValue(ParentProperty) as ItemsControl;

        public static void SetCurrentItem

            DependencyObject element, object value

            element.SetValue(CurrentItemProperty, value);

        public static void SetIndexedId

            DependencyObject element, string value

            value = string.Format(value,

                GetParent(element)

                .Items

                .IndexOf(GetCurrentItem(element)));

            element.SetValue(IndexedIdProperty, value);

        public static void SetParent

            DependencyObject element, ItemsControl value

            element.SetValue(ParentProperty, value);

        #endregion

namespace ThinkFarAhead.AutoAutomationId

    using System.Collections.Generic;

    using System.Windows.Controls;

    public partial class MainPage : UserControl

        #region Constructors and Destructors

        public MainPage()

            this.InitializeComponent();

            var list = new List<string>();

            list.Add("Zero");

            list.Add("One");

            list.Add("Two");

            list.Add("Three");

            list.Add("Four");

            list.Add("Five");

            list.Add("Six");

            list.Add("Seven");

            list.Add("Eight");

            list.Add("Nine");

            list.Add("Ten");

            this.ItemsControl.ItemsSource = list;

        #endregion

Hope it helps somebody!

Thursday, July 01, 2010