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POProblems binding a WPF ContextMenu to an ObservableCollection with a Converter
 

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  1. POProblems binding a WPF ContextMenu to an ObservableCollection with a Converter
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    <p>Perhaps there is a better way to do this, but here's where I'm at right now. I would like to bind a ContextMenu to an ObservableCollection of some complex type. A property on the complex type will determine the icon that is displayed in the menu item. The only way I knew to do this was to create a ComplexTypeToMenuItem converter and associate that with the binding. However, as soon as I add the converter to the binding the context menu no longer updates when the collection has changed. If I remove the converter and rely on ComplexType.ToString() then the menu items update just fine. However, there are no icons in this case.</p> <p>This can easily be reproduced with the following:</p> <p>First the XAML</p> <pre><code>&lt;Window x:Class="GoddamnContextMenuPosition.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:local="clr-namespace:GoddamnContextMenuPosition" Title="MainWindow" Height="350" Width="525"&gt; &lt;Window.Resources&gt; &lt;local:ComplexTypeToMenuItemConverter x:Key="ComplexTypeToMenuItemConverter" /&gt; &lt;/Window.Resources&gt; &lt;Grid&gt; &lt;TextBox Grid.Row="0" Text="Hooray"&gt; &lt;TextBox.ContextMenu&gt; &lt;ContextMenu ItemsSource="{Binding Objects, Source={x:Static local:Settings.Instance}, Converter={StaticResource ComplexTypeToMenuItemConverter}}"&gt; &lt;/ContextMenu&gt; &lt;/TextBox.ContextMenu&gt; &lt;/TextBox&gt; &lt;Button Grid.Row="1" Content="Add" Height="25" Width="50" Click="Button_Click"&gt;&lt;/Button&gt; &lt;/Grid&gt; &lt;/Window&gt; </code></pre> <p>And now the code</p> <pre><code>public partial class MainWindow : Window { public MainWindow() { InitializeComponent(); } private void Button_Click(object sender, RoutedEventArgs e) { Settings.Instance.Objects.Add(new ComplexType() { Text = "NEW", Type = 4 }); } } public class ComplexType { public ComplexType() { this.TimeStamp = DateTime.Now; } public string Text { get; set; } public int Type { get; set; } public DateTime TimeStamp { get; set; } } public class ComplexTypeToMenuItemConverter : IValueConverter { public object Convert(object value, Type targetType, object parameter, CultureInfo culture) { var values = value as IEnumerable&lt;ComplexType&gt;; if (values == null) { return new List&lt;MenuItem&gt; { new MenuItem { Header = "Unknown Value" } }; } IList&lt;MenuItem&gt; items = new List&lt;MenuItem&gt;(); foreach (ComplexType obj in values) { BitmapImage bitmap = new BitmapImage(); bitmap.BeginInit(); bitmap.UriSource = new Uri("1.png", UriKind.Relative); bitmap.EndInit(); Image image = new Image(); image.Width = 16; image.Source = bitmap; MenuItem menuItem = new MenuItem(); menuItem.Header = string.Format("{0} - {1}", obj.Text, obj.TimeStamp.ToShortTimeString()); menuItem.Icon = image; items.Add(menuItem); } return items; } public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture) { throw new NotImplementedException(); } } public class Settings { private static readonly Settings settings = new Settings(); private Settings() { this.Objects = new ObservableCollection&lt;ComplexType&gt; { new ComplexType { Text = "Item #1", Type = 1 } }; } public static Settings Instance { get { return settings; } } public ObservableCollection&lt;ComplexType&gt; Objects { get; private set; } } </code></pre> <p>Any help will be greatly appreciated!</p>
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