DataGridComboBoxColumn selectItem binding issue - wpf

Question

I am trying to create a ComboBox inside a DataGridand to do selectItem binding but when I write this code ,and I select an item in on ComboBox in the column, all the ComboBox items in the DataGrid's column are binding and shows the same selected item. I need to bind each ComboBox item with its selectedItem.
I would be happy to get an help.
this is my code:
<DataGridComboBoxColumn Header="CHOOSE" Width="0.7*"
DisplayMemberPath="Name" SelectedItemBinding="{Binding Path=SelectedReceiver,{RelativeSource FindAncestor, AncestorType={x:Type DataGrid}}, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}">
<DataGridComboBoxColumn.ElementStyle>
<Style TargetType="{x:Type ComboBox}">
<Setter Property="ItemsSource" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type DataGrid}}, Path=DataContext.RxList}" />
<Setter Property="ItemTemplate" >
<Setter.Value>
<DataTemplate>
<TextBlock Text="{Binding Path= Name}" Style="{StaticResource GroupBoxHeaderTextBlockStyle}" />
</DataTemplate>
</Setter.Value>
</Setter>
</Style>
</DataGridComboBoxColumn.ElementStyle >
<DataGridComboBoxColumn.EditingElementStyle>
<Style TargetType="{x:Type ComboBox}">
<Setter Property="ItemsSource" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type DataGrid}}, Path=DataContext.RxList }" />
<Setter Property="ItemTemplate">
<Setter.Value>
<DataTemplate>
<TextBlock Text="{Binding Path= Name}" Style="{StaticResource GroupBoxHeaderTextBlockStyle}"/>
</DataTemplate>
</Setter.Value>
</Setter>
</Style>
</DataGridComboBoxColumn.EditingElementStyle>
</DataGridComboBoxColumn>

Answer 1

You bind to DataGrid.ItemsSource.SomeList when you actually need to bind to DataGrid.ItemsSource[x].SomeList.
Basically your list and selected item will always be the same for each column. You can use a static list for your item-model-class (if the list stays the same) and a property for the SelectedItem.
<DataGridComboBoxColumn SelectedItemBinding="{Binding SelectedReceiver}"> <!-- Bind to current item's SelectedReceiver -->
<DataGridComboBoxColumn.ElementStyle>
<Style TargetType="{x:Type ComboBox}">
<Setter Property="ItemsSource" Value="{Binding Path=(modelNamespace:MyModel.RxList)}"/> <!-- Bind to static list property -->
</Style>
</DataGridComboBoxColumn.ElementStyle>
</DataGridComboBoxColumn>