Setting an Expander toDatagrid programmatically

Question

I'm creating a runtime expander and I want to add to my datagrid. Here's the code:

// Creazione Expander
var expGrid = new Expander { Name = "exp" };
var expStackPanel = new StackPanel { Name = "expStackPanel", Height = 30, Orientation=Orientation.Horizontal };

// Ciclo 
foreach (var column in GridData.Columns)
{
    var newtextBlock = new TextBlock
    {
        Style = this.FindResource("HeaderTextBlock") as Style,
        Width = 100,
        Text =  column.Header.ToString()
    };
    expStackPanel.Children.Add(newtextBlock);
}
expGrid.Content = expStackPanel;
//GridData.  //?? How to?

How I've the Expander but I dunno how to add to the datagrid GridData.

Answer 1

I will give you my sample of binding expander to DataGrid in cs code:

xaml code:

 <Window.Resources>
        <local:GroupToTitleConverter x:Key="groupToTitleConverter" />
    </Window.Resources>
    <Grid>
        <DataGrid x:Name="GridData" AutoGenerateColumns="False">
            <DataGrid.GroupStyle>
                <GroupStyle>
                    <GroupStyle.ContainerStyle>
                        <Style TargetType="{x:Type GroupItem}">
                            <Setter Property="Template">
                                <Setter.Value>
                                    <ControlTemplate TargetType="{x:Type GroupItem}">
                                        <Expander IsExpanded="True">
                                            <Expander.Header>
                                                <StackPanel Orientation="Horizontal">
                                                    <TextBlock Text="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type GroupItem}}, Converter={StaticResource ResourceKey=groupToTitleConverter}}" />
                                                </StackPanel>
                                            </Expander.Header>
                                            <Expander.Content>
                                                <ItemsPresenter />
                                            </Expander.Content>
                                        </Expander>
                                    </ControlTemplate>
                                </Setter.Value>
                            </Setter>
                        </Style>
                    </GroupStyle.ContainerStyle>
                </GroupStyle>
            </DataGrid.GroupStyle>
            <DataGrid.Columns>
                <DataGridTextColumn Header="MyName"  Binding="{Binding MyName}"/>
                <DataGridTextColumn Header="MyId" Binding="{Binding MyId}" />
            </DataGrid.Columns>
        </DataGrid>

    </Grid>

Cs code for binding:

 public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            ObservableCollection<MyClass> ltMyClass = new ObservableCollection<MyClass>()
            {
                new MyClass(){MyName="Name1",MyId="Id1"},
                new MyClass(){MyName="Name2",MyId="Id2"},
                new MyClass(){MyName="Name3",MyId="Id3"},
                new MyClass(){MyName="Name4",MyId="Id3"},
                new MyClass(){MyName="Name5",MyId="Id3"}
            };
            ListCollectionView collection = new ListCollectionView(ltMyClass);
            collection.GroupDescriptions.Add(new PropertyGroupDescription("MyId"));
            this.GridData.ItemsSource = collection;
        }
    public class MyClass
    {
        public string MyName { get; set; }
        public string MyId { get; set; }
    } 

    public class GroupToTitleConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            GroupItem groupItem = value as GroupItem;
            CollectionViewGroup collectionViewGroup = groupItem.Content as CollectionViewGroup;
            MyClass entryViewModel = collectionViewGroup.Items[0] as MyClass;
            string title = string.Format("{0} - {1}", entryViewModel.MyName, entryViewModel.MyId);
            return title;
        }

        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            throw new NotImplementedException();
        }
    }