combobox databinding selectedvalue event

Question

我想执行一些功能，当用户在组合框中选择一个不同的值。

我正在使用MVVM模式。

任何想法我如何在这种情况下数据绑定？

Answer 1

你会想绑定至SelectedValue，SelectedItem，或SelectedIndex取决于你想要做什么：

public class MyViewModel : INotifyPropertyChanged 
{ 
    public ObservableCollection<MyObj> MyCollection { get; private set; } 

    private MyObj _theItem; 
    public MyObj TheItem 
    { 
     get { return _theItem; } 
     set 
     { 
      if (Equals(value, _theItem)) return; 

      _theItem= value; 

      //Or however else you implement this... 
      OnPropertyChanged("TheItem"); 
      //Do something here.... OR 
      //This will trigger a PropertyChangedEvent if you're subscribed internally. 
     } 
    } 

    private string _theValue; 
    public string TheValue 
    { 
     get { return _theValue; } 
     set 
     { 
      if (Equals(value, _theValue)) return; 

      _theValue= value; 
      OnPropertyChanged("TheValue"); 
     } 
    } 

    private int _theIndex; 
    public int TheIndex 
    { 
     get { return _theIndex; } 
     set 
     { 
      if (Equals(value, _theIndex)) return; 

      _theIndex = value; 
      OnPropertyChanged("TheIndex"); 
     } 
    } 
} 

public class MyObj 
{ 
    public string PropA { get; set; } 
} 

<!-- Realistically, you'd only want to bind to one of those --> 
<!-- Most likely the SelectedItem for the best usage --> 
<ItemsControl ItemsSource="{Binding Path=MyCollection}" 
       SelectedItem="{Binding Path=TheItem}" 
       SelectedValue="{Binding Path=TheValue}" 
       SelectedIndex="{Binding Path=TheIndex}" 
       /> 

Answer 2

绑定到SelectedItem上的属性。 在属性的setter中，执行你的功能。 的SelectedItem = “{绑定路径= SomeProperty}”