从用户控件更改窗口标题

Question

I have a solution using prism with multiple shells. I've almost got it working, but there is one thing that is stumping me. Well, two, but the answer will be the same for both since both are an attribute of the main window.

I need to change the Title of the window when I inject a usercontrol into the Shell.

I'm using ViewModelLocator, IRegionManager, and running all of the navigation through the bootstrapper (Thank you Brian Lagunas for the fantastic pluralsight module, btw)

What I need to do is change the Title of the Shell window when a new view is injected into the content region. The views are all created as UserControls.

I currently have a standard binding for the Title in my shell.xaml code,

   Title="{Binding Title}"

and I'm using some very simple code in my ShellViewModel.cs to set it when the Shell initializes.

    public string ViewTitle = "<window title here>";
    public string Title
    {
       get { return ViewTitle; }
       set { if (ViewTitle != null) SetProperty(ref ViewTitle, value); }
    }

Answer 1

This is an old question but I am currently working through the same situation. I am relatively new to MVVM with Prism but wanted to record how I resolved this issue in the event someone else stumbled upon this while searching for an answer.

1. Create a new class that inherits from BindableBase and add a title property to it:

    public class BindableBaseExtended : BindableBase { private string _mainTitle; public string MainTitle { get { return _mainTitle; } set { _mainTitle = value; } } } 

2. In your MainWindow (or whatever you are using as a shell), Give your ContentControl a Name

    <ContentControl Grid.Row="1" x:Name="mainContent" prism:RegionManager.RegionName="... 

3. In your MainWindow(shell) bind to the content control element by name and path of where we will set the title:

    <TextBlock HorizontalAlignment="Center" VerticalAlignment="Center" FontSize="22" Text="{Binding Content.DataContext.MainTitle, ElementName=mainContent}" /> 

4. For your main content panels that will be feeding the title change, make them inherit from BindableBaseExtended (previously inheriting BindableBase):

    public class ViewBViewModel : BindableBaseExtended 

5. On instantiation of class (someone navigated there) set your MainTitle property:

    public ViewBViewModel(IEventAggregator eventAggregator) { _eventAggregator = eventAggregator; MainTitle = "View B"; eventAggregator.GetEvent<UpdateTitleEvent>().Subscribe(Updated); } 

Your property will now be feed through your user controls to your shell and will change upon navigation. Would love to hear any feedback on how to improve this or point me to where this has already been implemented in a more correct fashion but for now I wanted to share this version in the event any one else is stuck.