m3.M1.N = value.N;

m3.M1 = value.M1;

this.vm1 = new ViewModel1(this.m3.M1);

this.m3 = m3;

m3.M1 = value.M1;

class Model1
{
    public int N { get; set; }
}

class Model2
{
    public int N { get; set; }
}

class Model3
{
    public Model1 M1 { get; set; }
    public Model2 M2 { get; set; }
}

public class Department
{
    public int Id { get; set; }
    public string Title { get; set; }
    public IEnumerable<Department> Departments { get; set; }
}

class ViewModel3
{
    private Model3 m3;
    private ViewModel1 vm1;
    private ViewModel2 vm2;

    public ViewModel1 VM1
    {
        get { return vm1; }
        set 
        {
            vm1 = value;
            m3.M1.N = value.N;
            //m3.M1 = value.M1;
        }
    }

    public ViewModel3(Model3 m3)
    {
        this.m3 = m3;
        this.vm1 = new ViewModel1(this.m3.M1);
        this.vm2 = new ViewModel2(this.m3.M2);
    }
}

set { model.Property = value; }

set 
{
    vm1 = value;
    m3.M1.N = value.N;
    //m3.M1 = value.M1;
}

<UserControl>
	<ContentPresenter
		Content="{Binding Path=ViewModel1}" 
		/>
	<ContentPresenter
		Content="{Binding Path=ViewModel2}"
		/>
</UserControl>

class Model1 
{ 
    public int A { get; set; }
}

class Model2 
{
    public Model1 M1 { get; set; }
    
    public int B { get; set; }
}

class Model3 
{
    public Model2 M2 { get; set; }
    
    public int C { get; set; }
}

class Model4 
{
    public Model3 M3 { get; set; }
    
    public int D { get; set; }
}


class ViewModel4
{
    private Model4 m4;
    
    public ViewModel4(Model4 m4)
    {
        this.m4 = m4;
    }

    public int A { get { return m4.M3.M2.M1.A; }; }    
    public int B { get { return m4.M3.M2.B; }; }
    public int C { get { return m4.M3.C; }; }
    public int D { get { return m4.D; }; }
}

class Model1
{
    public int N { get; set; }
}

class Model2
{
    public Model1 Ma { get; set; }
    public Model1 Mb { get; set; }    
    public Model1 Mc { get; set; }
    public Model1 Md { get; set; }
}

var view = new EmployeeDetailWindow();
view.Owner = ActiveWindow;
view.DataContext = vm;

        public void UpdateDetailWindowAfterCreate(Employee employee)
        {
            var window = ActiveWindow;
            var grid = (DataGrid)window.FindName("employeesGrid");
            ((IList)grid.ItemsSource).Insert(0, employee);
            grid.SelectedItem = employee;
        }

<UserControl x:Class="BlogWeek3.ShellView"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
  <DockPanel>
    <ContentControl x:Name="CommandBar"
                    DockPanel.Dock="Top" />
 
    <ContentControl x:Name="Status"
                    DockPanel.Dock="Bottom" />
 
    <ListBox x:Name="Documents"
             DockPanel.Dock="Left" />
 
    <ContentControl x:Name="ActiveDocument" />
  </DockPanel>
</UserControl>

<UserControl x:Class="BlogWeek3.ShellView"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
  <DockPanel>
    <ContentControl x:Name="CommandBar"
                    DockPanel.Dock="Top" />
 
    <ContentControl x:Name="Status"
                    DockPanel.Dock="Bottom" />
 
    <ListBox x:Name="Documents"
             DockPanel.Dock="Left" />
 
    <ContentControl x:Name="ActiveDocument" />
  </DockPanel>
</UserControl>