I want to show the stream data to textbox in real time. But the textbox doesn't updated even the stream data has updated. I don't know what is wrong.

Here is my XAML code.

```
<TextBox Text="{Binding Path = marketPrice}" HorizontalAlignment="Left"/>

```

And this is View Model code.

```
public class OrderTestViewModel : INotifyPropertyChanged
{
     public QuotesDataSource DataSource;
     public string _marketPrice => DataSource.SymbolPrice;
     public string marketPrice
     {
         get { return _marketPrice; }
         set
         {
             RaisePropertyChanged("marketPrice");
         }
     }  
     public event PropertyChangedEventHandler PropertyChanged;
     public void RaisePropertyChanged(string propertyName)
     {
         if (PropertyChanged != null)
             PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
     }   
}

```

I checked the marketPrice is updated real time.

And the last is hidden code.

```
public partial class OrderTest : UserControl
{
   OrderTestViewModel model = new OrderTestViewModel();
   public OrderTest()
   {
       InitializeComponent();
       DataContext = model;
   }
}

```

Please help me.