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

Question

I have a ParentView that contains a childView
<UserControl ... x:Name="MyParentView">
<Grid>
<sdk:TabControl Name="ContactTabControl">
<sdk:TabItem Header="Contact" Name="CustomerTabItem">
<Grid>
<Views:CustomerView/>
</Grid>
</sdk:TabItem>
</sdk:TabControl>
</Grid>
</UserControl>
Within my CustomerView I would like to bind the Firstname textbox to Parent's DataContext. I have tried this inside the CustomerView:
<TextBox Text={Binding ElementName=MyParentView, Path=DataContext.Firstname} />
I have the feeling that CustomerView won't be able to see its parent at all, hence the ElementName "MyParentView" would never be found.
What is your advice on this?

Answer 1

I've done a similar thing but I just bound it directly to Path considering that if I don't give it explicit data context, it will lookup the hierarchy and find one that matches.
So this should get you what you want:
<TextBox Text={Binding Path=FirstName} />
if you need to specify explicit datacontext you can always do:
<Grid>
<Views:CustomerView DataContext={"CustomContextHere"}/>
</Grid>

Answer 2

An alternative solution to Maverik's is :
1 Define a dependency property in your customer view :
public partial class CustomerView : UserControl
{
public CustomerView()
{
InitializeComponent();
}
public static DependencyProperty FirstNameProperty =
DependencyProperty.Register("FirstName", typeof(string), typeof(CustomerView), new PropertyMetadata(string.Empty, CustomerView.FirstNameChanged));
public string FirstName
{
get { return (string)GetValue(FirstNameProperty); }
set { SetValue(FirstNameProperty, value); }
}
private static void FirstNameChanged(object sender, DependencyPropertyChangedEventArgs e)
{ }
}
2 Modify the customer view's textbox to bind to this dependency property (note the element binding "this")
<UserControl x:Class="SLApp.CustomerView"
x:Name="this"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Width="400" Height="300">
<Grid x:Name="LayoutRoot" Background="White">
<TextBox Text="{Binding Path=FirstName, ElementName=this, Mode=TwoWay}"/>
</Grid> </UserControl>
3 Modify the parent view and bind it's DataContext to the new dependency property
<sdk:TabControl Name="ContactTabControl">
<sdk:TabItem Header="Contact" Name="CustomerTabItem">
<Grid>
<local:CustomerView FirstName="{Binding ElementName=ContactTabControl, Path=DataContext}"/>
</Grid>
</sdk:TabItem>
</sdk:TabControl>
4 Set the parent's DataContext
public partial class MyParentView : UserControl
{
public MyParentView()
{
InitializeComponent();
ContactTabControl.DataContext = "A name";
}
}
Voila' it works. Not the most elegant solution but it gets the job done for your scenario