How to access Textbox GetBindingExpression in ViewModel

Hi,
Model- Person
ViewModel-MainWindowVW
View-MainWindow
Please help how to acces the textbox.getbindingexpression in viewmodel. Please refer sample code. 
i have used updatesourcetrigger=Explcit. After click the save button how to get the New Value in CurrentPerson.
Note: Please don't change updatesourcetrigger=Explcit
 public class Person : INotifyPropertyChanged
    {
        private string name;
        public string Name 
        {
            get { return name; }
            set 
            { 
                 name=value;
                PropChanged("Name");
            }
        }
        private int age;
        public int Age 
        {
            get { return age; }
            set
            {
                age = value;
                PropChanged("Age");
            }
        }

        public event PropertyChangedEventHandler PropertyChanged;

        public void PropChanged(string propertyName)
        {
            if (PropertyChanged != null)
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }

    public class RelayCommand : ICommand
    {
        Action<object> action;
        Predicate<object> predicate;
        public RelayCommand()
        {
        }
        public RelayCommand(Action<object> action,Predicate<object> predicate)
        {
            this.action = action;
            this.predicate = predicate;
        }

        public bool CanExecute(object parameter)
        {
            return predicate(parameter);
        }

        public event EventHandler CanExecuteChanged 
        {
            add { CommandManager.RequerySuggested += value; }
            remove { CommandManager.RequerySuggested -= value; }
        }

        public void Execute(object parameter)
        {
            action(parameter);
        }
    }

    public class MainWindowVW 
    {
        Person p;
        RelayCommand saveCommand ;
        RelayCommand cancelCommand;

        public MainWindowVW()
        {
            p = new Person() { Name = "Amru", Age = 24 };          
            saveCommand = new RelayCommand(SaveMethod, ValidateSave);
            cancelCommand = new RelayCommand(CloseMethod, ValidateClose);
        }

        public Person CurrentPerson
        {
            get { return p; }
        }

        public RelayCommand SaveCommand
        {
            get { return saveCommand; }
        }
        public RelayCommand CloseCommand
        {
            get { return cancelCommand; }
        }

        private bool ValidateSave(object p)
        {
            return true;
        }
        private bool ValidateClose(object p)
        {
            return true;
        }
        private void SaveMethod(object p)
        {
            this.CurrentPerson.PropChanged("Name");
            this.CurrentPerson.PropChanged("Age");          
            MessageBox.Show("[After] Name: " + this.CurrentPerson.Name + " Age: " + this.CurrentPerson.Age.ToString());
        }
        private void CloseMethod(object p)
        {
            Application.Current.MainWindow.Close();
        }
    }
  public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();            
            this.DataContext = new MainWindowVW();
        }       
    }<Window x:Class="Command_Explicit.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="125" Width="230" WindowStartupLocation="CenterScreen"><Grid FocusManager.FocusedElement="{Binding ElementName=txtName}"><Grid.RowDefinitions><RowDefinition Height="Auto"/><RowDefinition Height="Auto"/><RowDefinition Height="Auto"/></Grid.RowDefinitions><Grid.ColumnDefinitions><ColumnDefinition Width="40"/><ColumnDefinition Width="168"/></Grid.ColumnDefinitions><TextBlock Text="Name:" VerticalAlignment="Center" HorizontalAlignment="Right" Margin="3" Grid.Row="0"/><TextBlock Text="Age:" VerticalAlignment="Center" HorizontalAlignment="Right" Margin="3" Grid.Row="1"/><TextBox Name="txtName" VerticalAlignment="Center" HorizontalAlignment="Left" Margin="3" Grid.Row="0" Grid.Column="1" Width="160" TabIndex="0" Text="{Binding Path=CurrentPerson.Name,UpdateSourceTrigger=Explicit}"/><TextBox Name="txtAge" VerticalAlignment="Center" HorizontalAlignment="Left" Margin="3" Grid.Row="1" Grid.Column="1" Width="160"  TabIndex="1" Text="{Binding Path=CurrentPerson.Age,UpdateSourceTrigger=Explicit}"/><StackPanel Orientation="Horizontal" Grid.Row="2" Grid.Column="0" Grid.ColumnSpan="2" HorizontalAlignment="Right"><Button Name="btnSave" VerticalAlignment="Center" Width="60" Height="25" Margin="3" Content="Save" IsDefault="True" Command="{Binding SaveCommand}"/><Button Name="btnCancel" VerticalAlignment="Center" Width="60" Height="25" Margin="3" Content="Cancel" IsCancel="True" Command="{Binding CloseCommand}" /></StackPanel></Grid></Window>

Ahmed