DataBinding 2 ComboBoxes wpf - binding

Question

I need to build a form where I have 2 comboBoxes .
Select country and you get the cities of that country.
I m new to wpf so help me as I not sure what I am missing.
At the moment It doesnt even populate it.
Any help suggestions really appreaciated!
This is what I have done:
public partial class App : Application
{
protected override void OnStartup(StartupEventArgs e)
{
base.OnStartup(e);
var window = new MainWindow();
var countryCitymodel = new CountryCityModel();
var repository = new CountryCityRepository();
var viewModel = new CountryCityViewModel(countryCitymodel, repository);
window.Show();
}
}
MainWindow xaml
<Window x:Class="WpfDatabinding.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:view="clr-namespace:WpfDatabinding.Views"
Title="MainWindow" Height="350" Width="525">
<Grid>
<view:CountryCityView />
</Grid>
</Window>
CountryCityView xaml
<UserControl x:Class="WpfDatabinding.Views.CountryCityView"
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="75" d:DesignWidth="300">
<Grid Height="64" Width="291">
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="97"/>
<ColumnDefinition Width="13" />
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Label Content="Countries" Margin="-6,6,5,0" Grid.ColumnSpan="2" Height="33"></Label>
<Label Grid.Row="1" Content="Cities" Grid.ColumnSpan="2"></Label>
<ComboBox Name="cboCountries"
ItemsSource="{Binding Path=Countries}"
SelectedValuePath="Name"
DisplayMemberPath="{Binding Name}"
Grid.Column="2"
Margin="0,10"></ComboBox>
<ComboBox Name="cboCities"
Grid.Column="2"
Grid.Row="1"
ItemsSource="{Binding Path=Cities}" Height="20" Margin="0,0,0,1">
</ComboBox>
</Grid>
</UserControl>
CountryCityView
public partial class CountyrCityView:UserControl
{
public CountryCityView()
{
InitializeComponents();
}
public CountryCityView(CountryCityViewModel countryCityViewModel)
{
InitializeComponents();
DataContext=countryCityViewModel;
}
}
CountryCityViewModel
public class CountryCityViewModel : ViewModelBase
{
private readonly CountryCityModel _countryCityModel;
readonly CountryCityRepository _repository;
RelayCommand _getCountriesCommand;
private RelayCommand _getCitiesCommand;
public CountryCityViewModel(CountryCityModel countryCityModel, CountryCityRepository repository)
{
_countryCityModel = countryCityModel;
_repository = repository;
GetCountries.Execute(null);
}
public List<Country> Countries
{
get { return _countryCityModel.Countries; }
set
{
_countryCityModel.Countries = value;
OnPropertyChanged("Countries");
}
}
public List<City> Cities
{
get { return _countryCityModel.Cities; }
set
{
_countryCityModel.Cities = value;
OnPropertyChanged("Cities");
}
}
public Country SelectedCountry
{
get { return _countryCityModel.SelectedCountry; }
set
{
_countryCityModel.SelectedCountry = value;
OnPropertyChanged("SelectedCountry");
}
}
public City SelectedCity
{
get { return _countryCityModel.SelectedCity; }
set
{
_countryCityModel.SelectedCity = value;
OnPropertyChanged("SelectedCity");
}
}
public ICommand GetCountries
{
get
{
if (_getCountriesCommand == null)
{
_getCountriesCommand = new RelayCommand(param => GetCountryList(), param => CanGetCountries());
}
return _getCountriesCommand;
}
}
public ICommand GetCities
{
get
{
if (_getCitiesCommand == null)
{
_getCitiesCommand = new RelayCommand(param => GetCityList(), param => CanGetCities());
}
return _getCitiesCommand;
}
}
private List<Country> GetCountryList()
{
Countries = _repository.GetCountries();
return Countries;
}
private static bool CanGetCountries()
{
return true;
}
private List<City> GetCityList()
{
Cities = _repository.GetCities(SelectedCountry.Name);
return Cities;
}
private static bool CanGetCities()
{
return true;
}
}
Model
public class CountryCityModel
{
public List<Country> Countries { get; set; }
public List<City> Cities { get; set; }
public Country SelectedCountry{ get; set; }
public City SelectedCity { get; set; }
}
Types
public class City
{
public string Name { get; set; }
public string CountryName { get; set; }
}
public class Country
{
public string Name { get; set; }
}
Repository
public List<Country>GetCountries()
{
return new List<Country>
{
new Country{Name = "Italy"},
new Country{Name = "Germany"},
new Country{Name = "France"},
new Country{Name = "England"}
};
}
public List<City> GetCities(string countryName)
{
return Cities().Where(c => c.CountryName == countryName).ToList();
}
private static IEnumerable<City> Cities()
{
return new List<City>
{
new City { CountryName="Italy",Name = "Rome"},
new City {CountryName="France",Name = "Paris"},
new City{CountryName="Germany",Name ="Berlin"},
new City{CountryName="England",Name ="London"}
};
}
}

Answer 1

Are you setting the data context of the view to your ViewModel somewhere? I don't see that in the code listed above.
e.g.
var viewModel = new CountryCityViewModel(countryCitymodel, repository);
window.DataContext = viewModel;