WPF: How to customize SelectionBoxItem in ComboBox

Question

I want to display a custom template/item as selected item in ComboBox (this item does not actually exist in the list of items and is updated differently). This does not even

Answer 1

Alexey Mitev's comment on Ray Burns' answer inspired me to write the following reasonably short utility class, which I now use in all my WPF projects:

public class ComboBoxItemTemplateSelector : DataTemplateSelector
{
    public List SelectedItemTemplates { get; } = new List();
    public List DropDownItemTemplates { get; } = new List();

    public override DataTemplate SelectTemplate(object item, DependencyObject container)
    {
        return GetVisualParent(container) == null
            ? ChooseFrom(SelectedItemTemplates, item)
            : ChooseFrom(DropDownItemTemplates, item);
    }

    private static DataTemplate ChooseFrom(IEnumerable templates, object item)
    {
        if (item == null)
            return null;
        var targetType = item.GetType();
        return templates.FirstOrDefault(t => (t.DataType as Type) == targetType);
    }

    private static T GetVisualParent(DependencyObject child) where T : Visual
    {
        while (child != null && !(child is T))
            child = VisualTreeHelper.GetParent(child);
        return child as T;
    }
}

With that in the toolbox, it's possible to write XAML like this: