Changing color of label in C#, WPF, MVVM

Question

I have made a program with several pages. It is a simple program, where I have at top area also labels at which page you currently are. For every page it is a new label defined. All labels are defined in dockpanel.xaml which is later included to mainwindow.xaml.

I like to made current page label in different color.

MY CODE:

My DockPanel.xaml for first label (others are the same only number change)

<Label Name="Label1" Foreground="{Binding Path=Label1.Color}" Content="welcome" Grid.Column="0" HorizontalAlignment="Left" FontSize="20" FontWeight="Light" FontStyle="Italic"/>

My DockPanelViewModel

public class DockPanelViewModel : ViewModelBase
{
    #region Member fields

    #endregion

    #region Constructors
    /// <summary>
    /// The default constructor
    /// </summary>
    public DockPanelViewModel()
    {
    }
    #endregion

    #region Properties

    protected Brush _color;
    public Brush Color
    {
        get { return _color; }
        set
        {
            _color = value;
            NotifyPropertyChanged("Color");
        }
    }
    #endregion

}

Later definitions of ViewModel one of the page:

Label1.Color = System.Windows.Media.Brushes.Yellow;

The point is that my code dont want to change color and I dont know what is wrong :)

Please for help. Thanks!

Added .. PageViewModelBase

public virtual DockPanelViewModel Label1
    {
        get
        {
            if (_Label1 == null)
            {
                _Label1 = new DockPanelViewModel()
                {
                    //Text = "Back",
                    Color = System.Windows.Media.Brushes.Yellow,

                };
            }
            return _Label1;
        }
        set
        {
            _Label1 = value;
            NotifyPropertyChanged("Label1");
        }
    }

Solution

It's getting even worse now with the updated question. Please optimize and fix your namings!

To bring this to work, here's my suggestion:

1. Your DockPanelViewModel seems ok
2. Create an Instance of your DockPanelViewModel and assign it to the DataContext of your View
3. Bind the Foreground Property of your Label to {Binding Path=Color} (which is the Color Property of your viewModel
4. Remove the "Name" of the label (you don't need that in proper MVVM
5. Whenever you want to change the color of the label, just change the Color property if your viewmodel-instance (the one which you assigned to the view's DataContext)
6. I have no idea what this public virtual DockPanelViewModel Label1 you recently added to the question is. For me this seems unnecessary, delete it.

Here's a working example: View:

<Grid>
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="*"/>
        <ColumnDefinition Width="*"/>
    </Grid.ColumnDefinitions>
    <Label Grid.Column="0" Foreground="{Binding Path=LabelColor}" Content="welcome" FontSize="20" FontWeight="Light" FontStyle="Italic"/>
    <StackPanel Grid.Column="1">
        <Button Content="Red" Width="75" Command="{Binding ChangeColorCommand}" CommandParameter="#FF0000"/>
        <Button Content="Green" Width="75" Command="{Binding ChangeColorCommand}" CommandParameter="#00FF00" />
    </StackPanel>
</Grid>

View-Code:

public MainWindow()
{
    InitializeComponent();
    var vm = new ViewModel();
    DataContext = vm;
}

ViewModel:

public class ViewModel : INotifyPropertyChanged
{
    public ICommand ChangeColorCommand { get; set; }

    protected Brush _color;
    public Brush LabelColor
    {
        get { return _color; }
        set
        {
            _color = value;
            OnPropertyChange();
        }
    }

    public ViewModel()
    {
        LabelColor = Brushes.Yellow;
        ChangeColorCommand = new RelayCommand((o) =>
        {
            LabelColor = new BrushConverter().ConvertFromString(o.ToString()) as SolidColorBrush;
        });
    }

    public event PropertyChangedEventHandler PropertyChanged;

    private void OnPropertyChange([CallerMemberName] string propertyName = null)
    {
        var handler = PropertyChanged;
        if (handler != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

RelayCommand is the well-known standard class found everywhere on the web.