代码binding 和xaml binding的疑惑？

[Henry_Wu001]

xaml中TextBox作了如下binding,测试是成功的
<TextBox Text="{Binding Forename, Mode=TwoWay}" x:Name="myTB" Grid.Row="0" Grid.Column="1"/>

代码中的环境，
把一个PersonModel 的一个对象设为当前窗口的DataContext,（this.DataContext = Vm1;）
通过一个button事件修改DataContext的对象（this.DataContext = Vm2;）测试OK,TextBox的text属性会变化。

然后现在想用代码来实现xaml中的binding这块，却怎么也不变化。代码binding如下：
Binding binding1 = new Binding(“Forename”);
binding1.Source = this.DataContext;
this.myTB.SetBinding(TextBox.TextProp,binding1);

求教！！

 public class PersonModel : INotifyPropertyChanged
  {    
    private string _forename;
    public string Forename
    {
      get { return _forename; }
      set 
      {
        if (value == _forename)
          return;

        _forename = value;
        OnPropertyChanged("Forename");
      }
    }
}

[Henry_Wu001]

欧,解决了，如下:

  Binding binding = new Binding("DataContext.Forename");
            binding.RelativeSource = new RelativeSource(RelativeSourceMode.FindAncestor, typeof(Window), 1);
             
            binding.Mode = BindingMode.TwoWay;
            this.cityContext.SetBinding(TextBox.TextProperty, binding);

[Henry_Wu001]

better

  Binding binding = new Binding("DataContext.Forename");
            binding.Source = this;
            binding.Mode = BindingMode.TwoWay;
            this.cityContext.SetBinding(TextBox.TextProperty, binding);

[exception92]

binding 只要 设定好 源与目标，要绑定到的UIElement的某个依赖属性就ok了。