wpf master detail implementation with CRUDE options

wpf master detail implementation with CRUDE options

Allready have a two classes in master detail schema,
the master class has a collection of detail master, and need (want) to
perform all crude options inline.
Classes:
public partial class Items
{
public Items()
{
this.Detail = new HashSet<Detail>();
}
public decimal NumIdConcepto { get; set; }
public string StrDescripcionConcepto { get; set; }
public virtual ICollection<Detail> Detail { get; set; }
}
public partial class Detail
{
public int IntTipoAsociado { get; set; }
public decimal NumIdConcepto { get; set; }
public virtual Items Items { get; set; }
public virtual Master Master { get; set; }
}
public partial class Master
{
public Master()
{
this.Detail = new HashSet<Detail>();
}
public int IntTipoAsociado { get; set; }
public string StrDescripcionTipoAsociado { get; set; }
public virtual ICollection<Detail> Detail { get; set; }
}
For editing purposes and limitations of EF generator must perform a
conversion from HashSet to ObservableCollection for Detail collection of
Master
public class listToObservableCollection : BaseConverter, IValueConverter
{
public HashSet<Detail> JustForPath { get; set; }
public ObservableCollection<Detail> JustForPathObservable { get; set; }
public object Convert(object value, Type targetType, object parameter,
System.Globalization.CultureInfo culture)
{
HashSet<Detail> observableList = (HashSet<Detail>)value;
JustForPathObservable = new
ObservableCollection<Detail>(observableList);
return JustForPathObservable;
}
public object ConvertBack(object value, Type targetType, object
parameter, System.Globalization.CultureInfo culture)
{
JustForPath = (HashSet<Detail>)value;
return JustForPath;
}
}
public abstract class BaseConverter : MarkupExtension
{
public override object ProvideValue(IServiceProvider serviceProvider)
{
return this;
}
}
With this structure I want to generate a DataGrid wich allow me to add,
delete, and edit Detail In line, Don't want to call another forms
Like this:

My XAML code look like this:
<Window
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:ViewModels="clr-namespace:Contratos.ViewModels"
x:Class="Contratos.Views.TipoAsociado"
xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
xmlns:cmd="clr-namespace:GalaSoft.MvvmLight.Command;assembly=GalaSoft.MvvmLight.Extras.WPF45"
xmlns:l="clr-namespace:Recursos;assembly=Recursos"
Title="{Binding Title}" Height="Auto" Width="Auto">
<Window.DataContext>
<ViewModels:TipoAsociadoVM/>
</Window.DataContext>
<Window.Resources>
<l:listToObservableCollection x:Key="listoToObservable"/>
</Window.Resources>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<DataGrid Grid.Row="1"
ItemsSource="{Binding Master}"
AutoGenerateColumns="False"
SelectionMode="Single"
GridLinesVisibility="Vertical"
CanUserAddRows="True"
CanUserDeleteRows="True"
x:Name="GridTipoAsociado"
Margin="5"
SelectionChanged="GridTipoAsociado_SelectionChanged">
<i:Interaction.Triggers>
<i:EventTrigger EventName="SelectionChanged">
<cmd:EventToCommand Command="{Binding
_ICommandSelectionChange}"
PassEventArgsToCommand="True"/>
</i:EventTrigger>
</i:Interaction.Triggers>
<DataGrid.Columns>
<DataGridTemplateColumn Header="Description"
x:Name="Description">
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<Label Content="{Binding
StrDescripcionTipoAsociado}"/>
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
<DataGridTemplateColumn.CellEditingTemplate>
<DataTemplate>
<TextBox Text="{Binding StrDescripcionTipoAsociado
}"/>
</DataTemplate>
</DataGridTemplateColumn.CellEditingTemplate>
</DataGridTemplateColumn>
</DataGrid.Columns>
<DataGrid.RowDetailsTemplate>
<DataTemplate>
<DataGrid Grid.Row="1"
ItemsSource="{Binding
Path=Detail,Converter={StaticResource
listoToObservable},Mode=TwoWay}"
DisplayMemberPath="StrDescripcionConcepto"
AutoGenerateColumns="False"
IsSynchronizedWithCurrentItem="True"
SelectionMode="Single"
SelectionUnit="Cell"
GridLinesVisibility="Vertical"
CanUserAddRows="True"
CanUserDeleteRows="True"
x:Name="GridItems"
Margin="20,5,5,5">
<DataGrid.Columns>
<DataGridTemplateColumn Header="Items">
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<Label Content="{Binding
Items.StrDescripcionConcepto}"/>
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
<DataGridTemplateColumn.CellEditingTemplate>
<DataTemplate>
<!--
Here is my problem How can i to
bind to the propper values to
perform Editing
Without having this exception "TWO
WAY BINDING REQUIRES PATH OR
XPATH" when try to update DETAIL
items:
-->
<TextBox Text="{Binding
Items.StrDescripcionConcepto}"/>
</DataTemplate>
</DataGridTemplateColumn.CellEditingTemplate>
</DataGridTemplateColumn>
</DataGrid.Columns>
</DataGrid>
</DataTemplate>
</DataGrid.RowDetailsTemplate>
</DataGrid>
</Grid>
</Window>
Now, I need help on how to build a propper CellEditingTemplate, to allow
me edit all the changes that i need ?
Here is my problem How can i to bind to the propper values to perform
Editing Without having this exception "TWO WAY BINDING REQUIRES PATH OR
XPATH" when try to update DETAIL items?
NOTE: I don't want to create new Items, here, Just attach it to Detail