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POMy databinding with value converter does not work
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  1. POMy databinding with value converter does not work
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    copied!<p>I've got a simple Item-class, that looks like this:</p> <pre><code>public class Item : DependencyObject { public int No { get { return (int)GetValue(NoProperty); } set { SetValue(NoProperty, value); } } public string Name { get { return (string)GetValue(NameProperty); } set { SetValue(NameProperty, value); } } public static readonly DependencyProperty NoProperty = DependencyProperty.Register("No", typeof(int), typeof(Item)); public static readonly DependencyProperty NameProperty = DependencyProperty.Register("Name", typeof(string), typeof(Item)); } </code></pre> <p>And a ValueConverter, that looks like this:</p> <pre><code>[ValueConversion(typeof(Item), typeof(string))] internal class ItemToStringConverter : IValueConverter { public object Convert(object value, Type targetType, object parameter, CultureInfo culture) { if (value == null) { return null; } var item = ((Item)value); var sb = new StringBuilder(); sb.AppendFormat("Item # {0}", item.No); if (string.IsNullOrEmpty(item.Name) == false) { sb.AppendFormat(" - [{0}]", item.Name); } return sb.ToString(); } public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture) { throw new NotImplementedException(); } } </code></pre> <p>On my WPF Window, I declare a DependencyProperty (called Items) that holds a list of Item objects (List&lt; Item >) and creates a ComboBox that binds to this DependencyProperty using this XAML-code:</p> <pre><code>&lt;ComboBox ItemsSource="{Binding ElementName=mainWindow, Path=Items}"&gt; &lt;ComboBox.ItemTemplate&gt; &lt;DataTemplate&gt; &lt;TextBlock Text="{Binding Converter={StaticResource itemToStringConverter}}"/&gt; &lt;/DataTemplate&gt; &lt;/ComboBox.ItemTemplate&gt; &lt;/ComboBox&gt; </code></pre> <p>If I execute the code below once, the databinding works fine, howevery the value convertion fails if I execute it again:</p> <pre><code>var item1 = new Item {Name = "Item A", No = 1}; var item2 = new Item {Name = "Item B", No = 2}; var item3 = new Item {Name = "Item C", No = 3}; Items = new List&lt;Item&gt; {item1, item2, item3}; </code></pre> <p>The problem is, that the ItemToStringConverter.Convert method is now passed a string-object as the first parameter instead of an Item-object?</p> <p>What am I doing wrong?</p> <p>Regards, Kenneth</p>
 

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