在MVVM中实现ComboBox SelectionChanged

添加命名空间

xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"

添加引用

System.Windows.Interactivity

具体如下：

<ComboBox x:Name="fileComboBox" Margin="5"  Width="130"
         ToolTip="Flag" 
         ItemsSource="{Binding FileList, Mode=TwoWay}" SelectedIndex="0">
  <i:Interaction.Triggers>
     <i:EventTrigger EventName="SelectionChanged">
       <i:InvokeCommandAction Command="{Binding SelectionChangedCommand}"
         CommandParameter="{Binding SelectedItems, ElementName=fileComboBox}"/>
     </i:EventTrigger>
  </i:Interaction.Triggers>
</ComboBox>