WPF Trigger based on Object Type

Question

Is there a way to do a comparison on object type for a trigger?

<DataTrigger Binding="{Binding SelectedItem}" Value="SelectedItem's Type">
</DataTrigger>

Background: I have a Toolbar and I want to Hide button's depending on what subclass is currently set to the selected item object.

Thanks

Answer 1

Why not just use a converter that takes an object and returns a string of the object type?

Binding="{Binding SelectedItem, Converter={StaticResource ObjectToTypeString}}"

and define the converter as:

public class ObjectToTypeStringConverter : IValueConverter
{
    public object Convert(
     object value, Type targetType,
     object parameter, System.Globalization.CultureInfo culture)
    {
        return value.GetType().Name;            
    }

    public object ConvertBack(
     object value, Type targetType,
     object parameter, System.Globalization.CultureInfo culture)
    {
        // I don't think you'll need this
        throw new Exception("Can't convert back");
    }
}

You'll need to declare the static resource somewhere in your xaml:

<Window.Resources>
    <convs:ObjectToTypeStringConverter x:Key="ObjectToTypeString" />
</Window.Resources>

Where 'convs' in this case is the namespace of where the converter is.

Hope this helps.

Answer 2

Using a converter as suggested by AndyG is a good option. Alternatively, you could also use a different DataTemplate for each target type. WPF will automatically pick the DataTemplate that matches the object type