caliburn micro master detail - caliburn.micro

Question

I have looked at all the Caliburn Micro stuff I can find and I think I'm simply confusing myself. I put together a simple sample as a test.
Model = Person.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace WpfTestApp
{
public class Person
{
public string FirstName { get; set; }
public string LastName { get; set; }
}
}
PersonView.xaml
<UserControl x:Class="WpfTestApp.PersonView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
mc:Ignorable="d"
d:DesignHeight="300" d:DesignWidth="300">
<Grid>
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding FirstName}" />
<TextBlock Text="{Binding LastName}" />
</StackPanel>
</Grid>
</UserControl>
ShellViewModel.cs
using Caliburn.Micro;
using System.ComponentModel.Composition;
namespace WpfTestApp {
[Export(typeof(IShell))]
public class ShellViewModel : PropertyChangedBase, IShell
{
public BindableCollection<PersonViewModel> Items { get; set; }
public ShellViewModel()
{
Items = new BindableCollection<PersonViewModel> {
new PersonViewModel(new Person { FirstName="Bart", LastName="Simpson" }),
new PersonViewModel(new Person { FirstName="Lisa", LastName="Simpson" }),
new PersonViewModel(new Person { FirstName="Homer", LastName="Simpson" }),
new PersonViewModel(new Person { FirstName="Marge", LastName="Simpson" }),
new PersonViewModel(new Person { FirstName="Maggie", LastName="Simpson" })
};
}
}
}
ShellView.xaml
<Window x:Class="WpfTestApp.ShellView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:cal="http://www.caliburnproject.org">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<StackPanel>
<ListBox x:Name="Items"/>
</StackPanel>
<ContentControl cal:View.Model="{Binding SelectedItem, Mode=TwoWay}" Grid.Row="1" />
</Grid>
</Window>
I am using the MEFBootstrapper as per the Caliburn Micro documentation.
1) Why is that when I select an item in the ListBox, nothing appears in the ContentControl. I am obviously missing something but I thought SelectedItem was hooked up by the conventions. I've tried using x:Name="ActiveItem" and that did not work either?
2) How does this work if my ShellViewModel.cs contained a BindableCollection of Person instead of PersonViewModel?
3) Can I name the BindableCollection something other than Items (Yes - I know Items is a convention of Caliburn Micro)?
Regards
Alan

Answer 1

Make your ContentControl in ShellView as
<ContentControl Name="ActiveItem"/>
And them inherit your ShellViewModel from Conductor.Collection.OneActive
public class ShellViewModel : Conductor<IScreen>.Collection.OneActive, IShell
{
}
Since Conductor already have Items Property for Binding ChildView, please remove your Items property from ShellViewModel.
Also we have to write code to activate the View in ShellView
Change ListBox to
<ListBox x:Name="Items" cal:Message.Attach="[Event SelectionChanged]=[Action ActivateChildView($this.SelectedItem)]"/>
and inside ShellViewModel a new method
public void ActiveChildView(object view)
{
ActiveItem(view);
}
I have not tested it, but Hope this will work.

Answer 2

You actually need a public property on your view model called SelectedItem (of type PersonViewModel in this case), otherwise there will be nothing to bind to, and you won't be able to access the bound data item from your view model.
You could bind to a collection of Person directly instead. You could say that this breaks the Law of Demeter, but if your PersonViewModel doesn't augment the Person model with any additional data, then you might consider a view model surplus in this case.
Yes you can name it anything, and the conventions will still work, e.g. Users will by convention map to SelectedUser (or ActiveUser or CurrentUser). People won't by convention map to SelectedPerson, but you can alter the ConventionManager Singularize delegate if you wanted this functionality.