#506 – Using a ComboBox as GroupBox Header

Because the GroupBox.Header property can be set to any object, you could host a control in the header of the GroupBox.  In the example below, we specify a ComboBox for the Header and then bind the various fields to the selected item.

    <GroupBox Margin="15">
        <GroupBox.Header>
            <ComboBox Name="cboDogs" ItemsSource="{Binding Dogs}" DisplayMemberPath="Name"
                      SelectedIndex="0"
                      SelectedValue="{Binding SelectedDog}"
                      SelectedValuePath=""/>
        </GroupBox.Header>
        <Grid Margin="10" DataContext="{Binding SelectedDog}">
            <Grid.RowDefinitions>
                <RowDefinition Height="Auto"/>
                <RowDefinition Height="Auto"/>
                <RowDefinition/>
            </Grid.RowDefinitions>
            <Grid.ColumnDefinitions>
                <ColumnDefinition/>
                <ColumnDefinition/>
            </Grid.ColumnDefinitions>

            <Label Grid.Row="0" Grid.Column="0" Content="Name:" FontWeight="Bold" HorizontalAlignment="Right"/>
            <Label Grid.Row="0" Grid.Column="1" Content="{Binding Name}"/>
            <Label Grid.Row="1" Grid.Column="0" Content="Age:" FontWeight="Bold" HorizontalAlignment="Right"/>
            <Label Grid.Row="1" Grid.Column="1" Content="{Binding Age}" />
            <Label Grid.Row="2" Grid.Column="0" Content="Hobby:" FontWeight="Bold" HorizontalAlignment="Right"/>
            <Label Grid.Row="2" Grid.Column="1" Content="{Binding Hobby}"/>
        </Grid>
    </GroupBox>

    public partial class Window1 : Window, INotifyPropertyChanged
    {
        public Window1()
        {
            InitializeComponent();
            this.DataContext = this;

            Dogs = new ObservableCollection<Dog>();
            Dogs.Add(new Dog("Lassie", 12, "Saving people"));
            Dogs.Add(new Dog("Rin Tin Tin", 52, "War dog"));
            Dogs.Add(new Dog("Benji", 18, "Befriends strays"));
            OnPropertyChanged("Dogs");
        }

        public ObservableCollection<Dog> Dogs { get; protected set; }

        private Dog selectedDog;
        public Dog SelectedDog {
            get
            {
                return selectedDog;
            }
            set
            {
                if (value != selectedDog)
                {
                    selectedDog = value;
                    OnPropertyChanged("SelectedDog");
                }
            }
        }

        public event PropertyChangedEventHandler PropertyChanged = delegate { };

        private void OnPropertyChanged(string prop)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(prop));
        }
    }