內部元素必須通過Binding.ElementName(其中命名的UserControl是綁定源)或使用Binding.RelativeSource綁定到控件的屬性。 HeaderAndTextBox.xaml <UserControl> <TextBox Text="{Binding RelativeSource={RelativeSource AncestorType=UserControl}, Path=TextBoxContent, UpdateSourceTrigger=PropertyChanged}" /></UserControl> 接下來,確保托管HeaderAndTextBox的父元素的DataContext是正確的: MainWindow.xaml <Window> <Window.DataContext> <MyViewModel /> </Window.DataContext> <StackPanel> <!-- The HeaderAndTextBox inherits the parent's DataContext, which is MyViewModel, automatically. --> <HeaderAndTextBox Te