<ContentPresenter Content="{Binding SelectedCmbBoxID}" ContentTemplateSelector="{StaticResource MyObjTemplateSelector}"/>

<DataTemplate x:Key="DocTemplate" DataType="{x:Type local:MyObject}">
    <Grid>
       <...>
       <TextBox Grid.Row="1" Text="{Binding MyObj.DocDate}"/>
       <TextBox Grid.Row="2" Text="{Binding MyObj.DocNum }"/>
       <...>

public class MyData
{
    public string Name { get; set; }
    public string Address { get; set; }
    public string DocDate { get; set; }
    public string DocNum { get; set; }
    <...>
}

public class MyViewModel : INotifyPropertyChanged
{
    public MyData MyObject { get; set; }
    <...>
}

public MyWindow(MyViewModel vm)
{
    InitializeComponent();
    DataContext = vm;
}

<Window x:Class="MyProject.MyWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:local="clr-namespace:MyProject"/>
        <...>
    <Grid>
        <...>
        <TextBox Grid.Row="1" Text="{Binding MyObject.Name}"/>
        <TextBox Grid.Row="2" Text="{Binding MyObject.Address}"/>
        <...>

<DataTemplate x:Key="DocTemplate" DataType="{x:Type local:MyData}">
    <Grid>
       <...>
       <TextBox Grid.Row="1" Text="{Binding MyObject.DocDate}"/>
       <TextBox Grid.Row="2" Text="{Binding MyObject.DocNum }"/>
       <...>

public bool IsEditMode { get; set; }

<DataTemplate x:Key="DocTemplate" DataType="{x:Type local:MyData}">
    <ScrollViewer Style="{StaticResource ScrollViewerStyle}">
        <Grid>
        <...>


<Style x:Key="ScrollViewerStyle" TargetType="ScrollViewer">
    <Setter Property="VerticalScrollBarVisibility" Value="Auto"/>
    <Setter Property="DataContext" Value="{Binding DataContext, RelativeSource={RelativeSource AncestorType=Window}}"/>
</Style>

<ContentPresenter Content="{Binding MyObject}" ContentTemplate="{StaticResource DocTemplate}" />
    <ContentPresenter.Resources>
        <Style TargetType="TextBox">
            <Setter Property="IsReadOnly" Value="True"/>
        </Style>
    </ContentPresenter.Resources>
</ContentPresenter>

<ContentPresenter Content="{Binding MyObject}" ContentTemplate="{StaticResource DocTemplate}"/>

<ComboBox ItemsSource="{x:Static MyProject.MyDic}" DisplayMemberPath="Name" SelectedValue="{Binding SelectedDocTypeID}" SelectedValuePath="ID"/>

public int? SelectedDocTypeID
{
    get { return MyObject.DocTypeID; }
    set
    {
        MyObject.DocTypeID = value;
        OnPropertyChanged();
        OnPropertyChanged("MyObject");
    }
}