Question

I am using MVVM Light with SL4. My View’s are resolving their View Model via the locator, all is fine.

My problem is that one of my views has a property that I need to set in another view.

i.e. a HomeView can have many instances of a component view. But on that home view I want to set the property on the component view. I’ve tried adding a dependency property to the code behind of the view – which I can then set from HomeView, but my component view model does not pick it up.

Is this possible to do?

ComponentControl.cs

public enum CustomStyle
{
    Active,
    Draft,
    Completed
}

public class ComponentControl : Control
{
    public ComponentControl()
    {
        DefaultStyleKey = typeof (ComponentControl);
    }

    public CustomStyle CustomType
    {
        get { return (CustomStyle)GetValue(CustomTypeProperty); }
        set { SetValue(CustomTypeProperty, value); }
    }

    public static readonly DependencyProperty CustomTypeProperty =
        DependencyProperty.Register("CustomType",
        typeof(CustomStyle),
        typeof(ComponentControl), null);
}

ComponentViewModel.cs

public CustomStyle CustomType
{
    get { return _customType; }
    set
    {
        if (value == _customType)
            return;

        _customType = value;
        base.RaisePropertyChanged("CustomType");
    }
}
private CustomStyle _customType;

ComponentView.xaml.cs

public static readonly DependencyProperty CustomTypeProperty =
    DependencyProperty.Register("CustomType", 
    typeof(CustomStyle), 
    typeof(ComponentView), null);

public CustomStyle CustomType
{
    get { return (CustomStyle)GetValue(CustomTypeProperty); }
    set { SetValue(CustomTypeProperty, value); }
}

ComponentView.xaml

<Grid>
    <common:ComponentControl 
            DataContext="{Binding Path=WorkflowList, Mode=OneWay}" 
            CustomType="{Binding Path=CustomType, Mode=TwoWay, 
                                 ElementName=root}" />
</Grid>

HomeView.xaml

<Grid x:Name="LayoutRoot">
    <common:HomeControl x:Name="homeControl">
        <common:HomeControl.ActiveContent>
            <local:ComponentView x:Name="active" CustomType="Active" />
        </common:HomeControl.ActiveContent>
        <common:HomeControl.DraftContent>
            <local:ComponentView x:Name="draft" CustomType="Draft" />
        </common:HomeControl.DraftContent>
        <common:HomeControl.CompletedContent>
            <local:ComponentView x:Name="completed" CustomType="Completed" />
        </common:HomeControl.CompletedContent>
    </common:HomeControl>
</Grid>

Answer 1

I think I can help you a bit, a while ago I answered a similar question :

Silverlight: How to bind to parent view's DataContext?

The child view in my example contains a dependency property, which has it’s value set in the parent view. The child view binds to that dependency property using a binding with ElementName=”this”