Silverlight Data Binding in Nested Controls - silverlight-4.0

Question

Hi guys I am working with SL4 and MVVM application actually i am stuck some where i might be doing some thing wrong thats why need your help, here is my scenario
//suodo code
public class EmployeeModel
{
//code
Public List<Shifts> Employeeshifts{get;set;}
}
public class ShiftModel
{
//code
}
Viewmodel for main page
public class MainVM
{
MainVM()
{
EmployeeList = DateFromSomeService;
}
Public List<Employees> EmployeeList{get;set}
Public DelegateCommand ClickBindingCommand{get;set;}
}
MainPage.xaml
<ItemsControl ItemSource={Binding EmployeeList}>
<ItemTemplate>
<DataTemplate>
<controls:EmployeeControl/>
</DataTemplate>
</ItemTemplate>
</ItemsControl>
Employeecontro.xaml
<ItemsControl ItemSource={Binding EmployeeShifts}>
<ItemTemplate>
<DataTemplate>
<controls:ShiftControl Click={Binding ClickBindingCommand}/>//here is problem this command is in mainviewmodel
</DataTemplate>
</ItemTemplate>
</ItemsControl>
MainPage.cs
this.DataContext = new MainVM();
ClickBindingCommand is defined in main VM but it is bound within shift control and shiftcontrol's data context is shift class which is my model class. If I declare this command in my shift model class than it works, means if I click on shift control this property is called but I dont want this because I want it in my main view model, where am I wrong?
Should I declare it in my shift model class but in this way i will bind directly my model to my view?

Answer 1

Use a DataContextProxy or a RelativeSource Binding. This will allow your Command to bind/fire on your MainViewModel.
Another alternative is to use the Caliburn Micro framework. You can then attach an action to your button in the child and click events will bubble up to the parent.

Answer 2

This "toolkit" offers an implementation of FindAncestor in silverlight. Try this:
http://blog.thekieners.com/2010/09/08/relativesource-binding-with-findancestor-mode-in-silverlight/

Answer 3

I ran into this same issue and what fixed it for me was to name my UserControl then reference that name in the binding.
Here is the syntax:
{Binding ElementName=SomeTextBox, Path=Text}
Bind to the “Text” property of the element XAML
element with name=”SomeTextBox” or x:Name=”SomeTextBox”.
So here is my user control:
<UserControl
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
x:Class="SupportReports.Workflow.Portfolio.PortfolioManager"
mc:Ignorable="d"
Name="PortfolioManagerControl"
>
And here is the nested dataTemplate that binds to my command in my main view model
<cmd:EventToCommand Command="{Binding ElementName=PortfolioManagerControl, Path=DataContext.PortfolioManagerProjectSelectedCommand}" CommandParameter="{Binding Text, ElementName=ProjectName}" />