Define a custom property to bind to

Question

Is it possible to bind the items of the control within the user control to a property whose name is specified via binding?

Something like this, but without the error produced:

    <ItemsControl ItemsSource='{Binding Path=CheckListItems, ElementName=Root}'>
        <ItemsControl.ItemTemplate>
            <DataTemplate>
                <!-- What should I put below to replace the inner binding? -->
                <CheckBox Content='{Binding Path={Binding Path=ItemPropertyName, ElementName=Root}, Mode=OneTime}' />
            </DataTemplate>
        </ItemsControl.ItemTemplate>
    </ItemsControl>

Where

• CheckListItems (DP) is a collection of items (IList<SomeCustomContainerType>)
• ItemPropertyName (DP) is the name of the property within the SomeCustomContainerType that should be displayed as a check box text
• Root is the name of the User Control

The exception in this case is (expectedly) as following:

A 'Binding' cannot be set on the 'Path' property of type 'Binding'.
A 'Binding' can only be set on a DependencyProperty of a DependencyObject.

Basically I want to pass the property name whose text should be displayed in a checkbox somehow from outside. It doesn't have to be bindable, but should be settable from the XAML consuming the user control.

Answer 1

have you tried using DisplayMemberPath?

here is an example of how to use it

try this, and see if it works:

<ItemsControl ItemsSource="{Binding Path=CheckListItems, ElementName=Root}" DisplayMemberPath="{Binding ItemPropertyName, ElementName=Root}">
    <ItemsControl.ItemTemplate>
        <DataTemplate>
            <!-- What should I put below to replace the inner binding? -->
            <CheckBox Content="{Binding Mode=OneTime}" />
        </DataTemplate>
    </ItemsControl.ItemTemplate>
</ItemsControl>

Answer 2

A possibility would be to use a ValueConverter with a ConverterParameter as the name of the Property. In the ValueConverter implementation you could load the the Value with Reflection.

the converter could look something like that:

[ValueConversion(typeof(string), typeof(string))]
public class ReflectionConverter : IValueConverter
{
    public object Convert(object value, System.Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        if (parameter != null)
        {
            Type type = value.GetType();
            System.Reflection.PropertyInfo prop = type.GetProperty (parameter.ToString());
            return prop.GetValue(value, null);
        }
        return value;
    }

    public object ConvertBack(object value, System.Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        return null;
    }
}

• add errorhandling...

Answer 3

Simply replace your line with this:

<CheckBox Content="{Binding ItemPropertyName}" />