I have three kind of separate checkbox questions, all related to their use in the same datagrid.

1. I've loaded a datatable, `dtAll`, into a datagrid, `dgdList`,  and bound each column to the imported data.  The datagrid also has an initial column with checkboxes.  How can I determine which rows of data have been checked.  The intended functionality is for a user to mark two duplicates and merge together.  I need to be able to gather row data from the datatable or datagrid whenever the checkbox column is checked

2. When I group my datagrid into tables, below, it somehow turns off my ability to check more than one checkbox. Everytime i select a new row, it clears all previous checkboxes.  I would like to be able to check boxes in multiple rows.  (Further, I have to click twice, once to select the row, once to edit the value of the checkbox to true - it would be great if I could do it in a single click).

    

        Dim myView As System.ComponentModel.ICollectionView
        myView = CollectionViewSource.GetDefaultView(dtAll)
        myView.GroupDescriptions.Add(New PropertyGroupDescription("GROUP ID"))
        dgdList.ItemsSource = dtAll.DefaultView

3. I've added a checkbox to the group header.  When clicked, I'd like it to fill in each checkbox in all the rows inside of that group.  Is there any way I can do this as well?  If it helps, below is the Xaml code I'm using to split up groups of records

    

         <DataGrid.GroupStyle>
            <GroupStyle>
                <GroupStyle.HeaderTemplate>
                    <DataTemplate>
                        <StackPanel>
                            <TextBlock Text="{Binding Path=Name}" />
                        </StackPanel>
                    </DataTemplate>
                </GroupStyle.HeaderTemplate>
                <GroupStyle.ContainerStyle>
                    <Style TargetType="{x:Type GroupItem}" x:Name="Style1">
                        <Setter Property="Template" x:Name="Setter1">
                            <Setter.Value>
                                <ControlTemplate TargetType="{x:Type GroupItem}" x:Name="ControlTemplate1">
                                    <Expander IsExpanded="True" Name="Expander1">
                                        <Expander.Header>
                                            <StackPanel Orientation="Horizontal">
                                                <CheckBox Name="CheckBox9" />
                                                <TextBlock Text=" Exact Name Match Group #"/>
                                                <TextBlock Text="{Binding Path=Name}" />           
                                            </StackPanel>
                                        </Expander.Header>
                                        <ItemsPresenter />
                                    </Expander>
                                </ControlTemplate>
                            </Setter.Value>
                        </Setter>
                    </Style>
                </GroupStyle.ContainerStyle>
            </GroupStyle>
        </DataGrid.GroupStyle>