Update Screens and Conductors page on Wiki to document ConductWith

[KeithSwanger]

I am attempting to use Conductor.Collection.AllActive to house multiple unique UserControls within one screen.

When binding to the Items collection of a conductor, how can I specify which VM will be used in a ContentControl?

This seems to work: <ContentControl s:View.Model="{Binding Items[0]}" />

However, when I close the screen, I get this error:

System.Windows.Data Error: 17 : Cannot get 'Item[]' value (type 'IScreen') from 'Items' (type 'BindableCollection`1'). BindingExpression:Path=Items[0]; DataItem='MainViewModel' (HashCode=48883615); target element is 'ContentControl' (Name=''); target property is 'Model' (type 'Object') ArgumentOutOfRangeException:'System.ArgumentOutOfRangeException: Specified argument was out of the range of valid values.
Parameter name: index'

My assessment from the error is that the VM is being deleted before the View, and it's trying to directly access an array element that doesn't exist any more. I don't get a crash, just an error in the console.

My main view is a UserControl split into sections which each house its own UserControl. I want to be able to specify which Item from the Conductor's Items collection each UserControl uses. Is there a better/safer way than accessing the Items collection at a specific element?

[canton7]

I think your assessment is correct.

If you're not binding Items to an ItemsControl (and you're instead binding UI controls to specific child VMs), I wouldn't bother with a conductor. I'd do:

public class MainViewModel : Screen
{
    public SomeViewModel SomeViewModel { get; }
    public OtherViewModel OtherViewModel { get; }

    public MainViewModel(...)
    {
        SomeViewModel = ...;
        SomeViewModel.ConductWith(this);

        OtherViewModel = ...;
        OtherViewModel.ConductWith(this);
    }
}

Then bind directly to SomeViewModel and OtherViewModel.

Conductors are useful when the set of children can change over time. If there is a static set of children, ConductWith is fine.

[KeithSwanger]

Oh, that's beautiful. It works perfectly.

This might be worth mentioning on the Conductors wiki page, because wow, that is so useful.

Thank you for this awesome framework!

[canton7]

That's fair, I'll update the wiki page.

(That particular bit of functionality was copied from Caliburn.Micro)