Dependency Injection not working - wpf

Question

I have been learning MVVM / WPF and have gone through the tutorial here.
I have created a working application using this methodology but now, on a new project, I cannot get the Dependency Injection to work.
When I run this project I get an empty MainWindow without the CompanyView injected. I have double and tripled checked everything between the project that works and this one that doesn't and cannot find the reason for CompanyView not being injected. I have also tried cleaning the solution and restarting VS to no avail. Hopefully someone can see what I am missing.
I have the following file:
App.xaml.cs (using base.OnStartup() instead of StartupUri in App.xaml)
namespace SidekickAdmin
{
/// <summary>
/// Interaction logic for App.xaml
/// </summary>
public partial class App : Application
{
protected override void OnStartup(StartupEventArgs e)
{
base.OnStartup(e);
MainWindow window = new MainWindow();
var viewModel = new MainWindowViewModel();
window.DataContext = viewModel;
window.Show();
}
}
}
MainWindowViewModel.cs
namespace SidekickAdmin.ViewModel
{
class MainWindowViewModel : ViewModelBase
{
public MainWindowViewModel()
{
CompanyViewModel companyViewModel = new CompanyViewModel(_repository);
this.ViewModels.Add(companyViewModel);
}
ObservableCollection<ViewModelBase> _viewModels;
ObservableCollection<ViewModelBase> ViewModels
{
get
{
if (_viewModels == null)
{
_viewModels = new ObservableCollection<ViewModelBase>();
}
return _viewModels;
}
}
}
}
MainWindowView.xaml
<Window x:Class="SidekickAdmin.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:vm="clr-namespace:SidekickAdmin.ViewModel"
xmlns:vw="clr-namespace:SidekickAdmin.View"
Title="Sidekick Admin" SizeToContent="WidthAndHeight">
<!-- Typically done in a resources dictionary -->
<Window.Resources>
<ResourceDictionary Source="MainWindowResources.xaml" />
</Window.Resources>
<StackPanel>
<ItemsControl ItemsSource="{Binding ViewModel}" Margin="3" />
</StackPanel>
</Window>
MainWindowResources.xaml
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:vm="clr-namespace:SidekickAdmin.ViewModel"
xmlns:vw="clr-namespace:SidekickAdmin.View">
<DataTemplate DataType="{x:Type vm:CompanyViewModel}">
<vw:CompanyView />
</DataTemplate>
</ResourceDictionary>
CompanyViewModel.cs (not really used yet as I am still trying to just get the view to appear)
namespace SidekickAdmin.ViewModel
{
class CompanyViewModel : ViewModelBase
{
readonly GenericRepository _repository;
#region Getters & Setters
public ObservableCollection<Company> AllCompanies
{
get;
private set;
}
#endregion
#region Constructors
public CompanyViewModel(GenericRepository repository)
{
if (repository == null)
{
throw new ArgumentNullException("repository");
}
_repository = repository;
this.AllCompanies = new ObservableCollection<Company>(_repository.GetAll<Company>());
}
#endregion
protected override void OnDispose()
{
this.AllCompanies.Clear();
}
}
}
CompanyView.xaml
<UserControl x:Class="SidekickAdmin.View.CompanyView"
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"
Height="300" Width="300">
<StackPanel>
<TextBlock>You say Hello</TextBlock>
<TextBlock>And I say Goodbye</TextBlock>
<TextBlock>Hello, Hello</TextBlock>
</StackPanel>
</UserControl>

Answer 1

Lester's comment is right... you are binding to a ViewModel property which does not exist - MainWindowViewModel has a ViewModels property though. The s is important

Answer 2

Besides what #Robert Levy has wrote, the error you are making is that your ViewModels property is private, make it public and it should work fine.

Answer 3

#RobertLevy and #dmusial are correct. You need to make your reference to ViewModels in your XAML plural, to match the property name in your C# code. Also, the property should be public, so the View can see it.