WPF

public DateTime A
{
   get
     {
         return _A;
     }
   set
     {
         _A=value;
         RaisePropertyChanged("A");
     }
}

public DateTime B
{
   get
     {
         return _B;
     }
   set
     {
         _B=value;
         RaisePropertyChanged("B");
     }
}

protected override String ValidateProperty(String propertyName)
{
     switch (propertyName)
     {
          case "A":
              //Do whatever
              break;
     }

}

public DateTime A
        {
            get
            {
                return _A;
            }
            set
            {
                _A = value;
                RaisePropertyChanged("A");
                RaisePropertyChanged("B");
            }
        }

        public DateTime B
        {
            get
            {
                return _B;
            }
            set
            {
                _B = value;
                RaisePropertyChanged("B");
                RaisePropertyChanged("A");
            }
        }

public String Property
{
    get
    {
        return _Property;
    }
    get
    {
        _Property=value;
        RaisePropertyChanged("Property");
    }
}

ObservableProperty String MyProperty;

If ofd.ShowDialog = Forms.DialogResult.OK Then

Dim result? As Boolean = ofd.ShowDialog()
If result = True Then

public class Factory
    {
        public string Name { get; set; }
    }
    public class Factories : ObservableCollection<Factory>
    {
        public Factories()
        {
            for (int i = 0; i < 5; i++)
            {
                Factory factory = new Factory() { Name = "Factory " + i.ToString() };
                this.Add(factory);
            }
        }
    }

public Factories AllFactories { get; set; }
        Factory currentFactory;
        public Factory CurrentFactory 
        {
            get
            {
                return currentFactory;
            }
            set
            {
                currentFactory = value;
                NotifyPropertyChanged("CurrentFactory");
            }
        }

        public MainWindow()
        {
            InitializeComponent();
            AllFactories = new Factories();
            this.DataContext = this;
        }

        public event PropertyChangedEventHandler PropertyChanged;
        public void NotifyPropertyChanged(String info)
        {
            PropertyChangedEventHandler handler = PropertyChanged;

            if (handler != null)
            {
                handler(this, new PropertyChangedEventArgs(info));
            }
        }

<Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"/>
            <RowDefinition />
        </Grid.RowDefinitions>
        <Grid.Resources>
            <DataTemplate DataType="{x:Type local:Factory}">
                <TextBlock  Text="{Binding Path=Name}"/>
            </DataTemplate>
        </Grid.Resources>
        <ComboBox ItemsSource="{Binding Path=AllFactories}" SelectedItem="{Binding Path=CurrentFactory, Mode=TwoWay}"/>
        <TabControl Name="tcMain" Grid.Row="1" DataContext="{Binding}" ItemsSource="{Binding Path=AllFactories}"
                    IsSynchronizedWithCurrentItem="True" SelectedItem="{Binding Path=CurrentFactory, Mode=TwoWay}">
            <TabControl.ItemTemplate>
                <DataTemplate>
                    <DockPanel >
                        <Label Content="{Binding Path=Name}" Margin="3"/>
                    </DockPanel>
                </DataTemplate>
            </TabControl.ItemTemplate>
        </TabControl>
    </Grid>