WPF data grid combo box column selected item data binding in C# - data-binding

Question

When I change selection in combo box debugger will hit TestSelectedItem {set} in User class, but I want to hit debugger, TestSelectedItem {set} in MainWindow class. Please suggests me correct solution.
public class User
{
public string Name { get; set; }
public ObservableCollection<string> TypeCollection { get; set; }
private string _testSelectedItem;
public string TestSelectedItem
{
get { return _testSelectedItem; }
set { _testSelectedItem = value; }
}
public User()
{
TypeCollection = new ObservableCollection<string>();
TypeCollection.Add("A");
TypeCollection.Add("B");
TypeCollection.Add("C");
}
}
public partial class MainWindow : Window
{
public List<User> Users { get; set; }
private string _testSelectedItem;
public string TestSelectedItem
{
get { return _testSelectedItem; }
set { _testSelectedItem = value; }
}
public MainWindow()
{
InitializeComponent();
Users = new List<User>();
Users.Add(new User() { Name = "User 1" });
Users.Add(new User() { Name = "User 2" });
Users.Add(new User() { Name = "User 3" });
myGrid.DataContext = this;
}
}
<Window x:Class="WpfApplication11.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:WpfApplication11"
mc:Ignorable="d"
Title="MainWindow" Height="350" Width="525">
<Grid Name ="myGrid">
<StackPanel>
<DataGrid Name="MyDataGrid" AutoGenerateColumns="False" ItemsSource="{Binding Users}">
<DataGrid.Columns>
<DataGridTextColumn Binding="{Binding Name}"
Header="Name"
Width="90"
CanUserResize="False"
CanUserSort="False"
CanUserReorder="False"
IsReadOnly="True" />
<DataGridComboBoxColumn Header="Product Type"
DisplayMemberPath="ProductType"
SelectedValuePath="ProductTypeId"
SelectedValueBinding="{Binding SelectedValuePath, UpdateSourceTrigger=PropertyChanged}">
<DataGridComboBoxColumn.ElementStyle>
<Style TargetType="{x:Type ComboBox}">
<Setter Property="ItemsSource" Value="{Binding TypeCollection}"/>
<Setter Property="VerticalAlignment" Value="Center"/>
</Style>
</DataGridComboBoxColumn.ElementStyle>
<DataGridComboBoxColumn.EditingElementStyle>
<Style TargetType="{x:Type ComboBox}">
<Setter Property="ItemsSource" Value="{Binding TypeCollection}"/>
<Setter Property="VerticalAlignment" Value="Center"/>
</Style>
</DataGridComboBoxColumn.EditingElementStyle>
</DataGridComboBoxColumn>
<DataGridTemplateColumn Header="Bug">
<DataGridTemplateColumn.CellTemplate >
<DataTemplate>
<ComboBox Height="25" Width="200"
x:Name ="ppCombo"
ItemsSource="{Binding TypeCollection }"
SelectedItem="{Binding TestSelectedItem ,Mode=TwoWay ,UpdateSourceTrigger=PropertyChanged}">
</ComboBox>
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
</DataGrid.Columns>
</DataGrid>
</StackPanel>
</Grid>
</Window>

Answer 1

I think I just found a solution but not sure is that the correct one
SelectedItem="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type local:MainWindow}}, Path=TestSelectedItem}">