Question

I have userControl with a GridView of GridViews (A GridView who’s data context is another GridView) so when i set the itemssource to a collection of collection i can see a hierarchical view.

eg:

Parent Collection is List<ClassRoom> and the parent Collection has a Property List<Student>

The above Classes are defined and i can’t modify the class(as we consider it is in Model Layer) for the use of my UserControl.

Because i am developing a UserControl i have defined a Property called bool ShowChildItems.

if ShowChildItems is set to false i want the childGridView to be Collapsed.

How can i bind the property of the user control to childGridView.Visisbility.
(ShowChildItems property value may change at runtime,depending on the instance of the UserControl)

Answer 1

To have a ShowChildItems property in your UserControl to manage the Visibility of your child GridView you first need to make it a DependencyProperty:

public static readonly DependencyProperty ShowChildItemsProperty =
    DependencyProperty.Register("showChildItems", typeof (bool), typeof (MyUserControl), new PropertyMetadata(true));

public bool ShowChildItems
{
    get { return (bool) GetValue(ShowChildItemsProperty); }
    set { SetValue(ShowChildItemsProperty, value); }
}

Inside the UserControl you will bind the GridView Visibility to this property by using the ElementName syntax – this way it doesn’t matter what the GridView DataContext is bound to:

<GridView Visibility="{Binding ShowChildItems, ElementName=ControlRoot, Converter={StaticResource VisibilityConverter}}" ItemsSource="{Binding ChildItems}">

For this to work you need to set the name to UserControl‘s root node (I’ve omitted the rest of the attributes):

<UserControl
    x:Name="ControlRoot">

I’ve also used a converter to bind a bool property to Visibility:

<UserControl.Resources>
    <local:BoolToVisibilityConverter x:Key="VisibilityConverter" />
</UserControl.Resources>

This is its code:

public class BoolToVisibilityConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, string language)
    {
        if (!(value is bool)) return Visibility.Collapsed;

        return (bool) value ? Visibility.Visible : Visibility.Collapsed;
    }

    public object ConvertBack(object value, Type targetType, object parameter, string language)
    {
        throw new NotImplementedException();
    }
}

I hope this is what you were asking for. I’m not quite sure based on your question.