How to change ToolTip binding programmatically?

I know that in XAML you can change a ToolTip's binding with...开发者_高级运维

<TextBlock Text="ABC" ToolTip="{Binding Path=SomeProperty}" /> 

How can I set the same binding for the tooltip programmatically?

XAML:

<TextBlock Text="ABC" x:Name="_textBlock" />

Code:

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
        this.DataContext = new Data{ Tip="Help!" };

        Binding binding = new Binding("Tip");

        _textBlock.SetBinding(TextBlock.ToolTipProperty, binding);
    }
}

try new Binding{Path="SomeProperty"}