How to bind the value of Selected Item in a combobox in DataGridHeader to one specific column not to all Datagrid columns in wpf?

Question

I have a DataGrid which has been filled with a DataTable using Itemsources properties, it means that all columns and rows have been created automatically.I need to add a combobox to each column header cell in my grid.

I have done that part using this piece of code :

<DataGrid Grid.Row="1" Margin="0 5 0 0" ItemsSource="{Binding SelectedExcel}">
   <DataGrid.ColumnHeaderStyle>
         <Style TargetType="{x:Type DataGridColumnHeader}">
             <Setter Property="ContentTemplate">
                 <Setter.Value>
                     <DataTemplate Template="">
                         <ComboBox ItemsSource="{Binding DataContext.ArticleAttributes, Source={x:Reference control}}" SelectedItem="{Binding DataContext.SelectedArticleAttribute, Source={x:Reference control}, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>
                     </DataTemplate>
                 </Setter.Value>
             </Setter>
         </Style>
   </DataGrid.ColumnHeaderStyle>
</DataGrid>

The problem is when I select one of the items in one of the comboboxes the value of all the comboboxes will be changed. I have attached an image. Any idea how should I fix that? And also I need to know the combobox of which column has been set. I need to use that column later. I am well aware of DataGrid SelectedItem and SelectedIndex properties, any other ideas?

I tried to fix it this way:

<DataGrid.ColumnHeaderStyle>
                <Style TargetType="{x:Type DataGridColumnHeader}">
                    <Style.Triggers>
                        <DataTrigger Value="True">
                            <DataTrigger.Binding>
                                <MultiBinding Converter="{StaticResource MultiEquilityConverter}">
                                    <Binding RelativeSource="{RelativeSource Self}" />
                                    <Binding Path="CurrentColumn" RelativeSource="{RelativeSource FindAncestor, AncestorType={x:Type DataGrid}}" />
                                </MultiBinding>
                            </DataTrigger.Binding>
                        </DataTrigger>
                    </Style.Triggers>
                    <Setter Property="ContentTemplate">
                        <Setter.Value>
                            <DataTemplate>
                                <ComboBox ItemsSource="{Binding DataContext.ArticleAttributes, Source={x:Reference control}}" SelectedItem="{Binding DataContext.SelectedArticleAttribute, Source={x:Reference control}, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>
                            </DataTemplate>
                        </Setter.Value>
                    </Setter>
                </Style>
            </DataGrid.ColumnHeaderStyle>

But the MultiEquilityConverter never fires.

I have been searching internet for two days, but I did not find any way yet.

Answer 1

I have fixed it this way, for the combo boxes I have used this piece of code :

<DataGrid.ColumnHeaderStyle>
                <Style TargetType="{x:Type DataGridColumnHeader}">
                    <EventSetter Event="Click" Handler="ColumnHeaderClick" />
                    <Setter Property="ContentTemplate">
                        <Setter.Value>
                            <DataTemplate>
                                <ComboBox ItemsSource="{Binding DataContext.ArticleAttributes, Source={x:Reference control}}">
                                    <l:Interaction.Triggers>
                                        <l:EventTrigger EventName="SelectionChanged">
                                            <l:InvokeCommandAction Command="{Binding DataContext.ArticleAttributeCommand, Source={x:Reference control}}" CommandParameter="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ComboBox}}, Path=SelectedItem}" />
                                        </l:EventTrigger>
                                    </l:Interaction.Triggers>
                                </ComboBox>
                            </DataTemplate>
                        </Setter.Value>
                    </Setter>
                </Style>
            </DataGrid.ColumnHeaderStyle>

And for getting the column number this way :

<EventSetter Event="Click" Handler="ColumnHeaderClick" />

As it has been mentioned above.

Answer 2

SelectedItem="{Binding DataContext.SelectedArticleAttribute, Source={x:Reference control}, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"

Every ComboBox in grid headers has SelectedItem bound to the same property SelectedArticleAttribute. Because of that, when one Combo changes SelectedItem that change will be propagated through bindings to all comboboxes

Not sure what’s the purpose of SelectedArticleAtribute in your DataContext. Maybe you could create separate property for every combobox and Bind them accordingly. (SelectedArticleAtribute1,SelectedArticleAttribute2,....)