View Models and View in WPF

Hi guys I have a wpf application that is using the mvvm pattern, in my application I have two view model, One controls my main window and the other control my page. I want to be able to bind my login page UI element to my LoginViewModel? Any idea on what to do thanks below is my code for my two view model

Main Window view model

#region Displayed page
       private Uri displayedPage;

       public Uri DisplayedPage
       {
           get
           {
               return this.displayedPage;
           }
           set
           {
               this.displayedPage = value;
               base.OnPropertyChanged("DisplayedPage");
           }
       }

       #endregion
       #endregion

       #region Constructor
       public MainWindowViewModel()
       {
           LoginViewModel _login = new LoginViewModel(this);
       }
       #endregion

while the view model for my page

#region Constructor
        public LoginViewModel(MainWindowViewModel _mainwin)
        {
            _mainViewModel = _mainwin;
            _mainViewModel.DisplayedPage = new Uri("/View/AuthenticationView/LoginPage.xaml", UriKind.RelativeOrAbsolute);
        }
        #endregion

and this is the code for my page

<TextBlock Grid.Row="2" HorizontalAlignment="Left" Name="UsrNmTxtBlk" Text="Username :" VerticalAlignment="Top" Padding="3" Margin="3,0,0,0" Grid.ColumnSpan="2" />
        <TextBox Grid.Row="3" Height="40" Name="UserNmTxtBx" Margin="3" Grid.ColumnSpan="2" VerticalContentAlignment="Center" Text="{Binding Path=OperatorUserID}"/>
        <TextBlock Grid.Row="4" HorizontalAlignment="Left" Name="UsrPassBlk" Text="Password :" VerticalAlignment="Top" Padding="3" Grid.ColumnSpan="2" />
        <PasswordBox Grid.Row="5" Height="40" HorizontalAlignment="Stretch" Name="UserPassTxtbx" Margin="3" Grid.ColumnSpan="2" VerticalContentAlignment="Center" 
                     passhelper:PasswordBxHelper.BindPassword="True"
                     passhelper:PasswordBxHelper.BoundPassword="{Binding Path=OperatorPassword}"/>
        <Button Content="Login" Grid.Column="1" Grid.Row="6" Height="40" 
                HorizontalAlignment="Right" Margin="3" Name="LogInBtn" 
                Width="78" Grid.ColumnSpan="2" />

Tags: C# (C# 4.0), WPF, MVVM