使用 Interaction 里面的方法来将事件映射到ViewModel层

引用命名空间：System.Windows.Interactivity.dll

在xaml界面引用这两种任意一个就行，这两个做的事情是相同的。

xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"

<Window x:Class="WpfApplication1.MainWindow"xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"Title="MainWindow" Height="350" Width="525"><!--xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"--><!--页面加载命令--><i:Interaction.Triggers><i:EventTrigger EventName="Loaded"><i:InvokeCommandAction Command="{Binding Page_Loaded}" /></i:EventTrigger></i:Interaction.Triggers><i:Interaction.Behaviors><c:WindowBehavior Close="{Binding ToClose}" /></i:Interaction.Behaviors><Grid><ComboBox x:Name="cb_kaname" IsReadOnly="False" BorderThickness="1"  BorderBrush="#999999" ItemsSource="{Binding lst_KaLei, Mode=TwoWay}" SelectedItem="{Binding Sel_Kalei, Mode=TwoWay}" Text="{Binding new_ka_name, Mode=TwoWay}" DisplayMemberPath="ka_name" Width="Auto" MinWidth="80" MaxWidth="200" IsEditable="True"><i:Interaction.Triggers><i:EventTrigger EventName="SelectionChanged"><i:InvokeCommandAction Command="{Binding cb_kaname_SelectionChanged}" CommandParameter="{Binding ElementName=cb_kaname}" /></i:EventTrigger></i:Interaction.Triggers></ComboBox><TextBox Name="tb_dazhebilvamount" Background="Transparent" Style="{StaticResource input_textbox}" MaxLength="3" HorizontalContentAlignment="Center" Text="{Binding new_faka_dazhebilv, Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"><intr:Interaction.Triggers><intr:EventTrigger EventName="TextChanged">    <intr:InvokeCommandAction Command="{Binding txt_TextChanged,TargetNullValue='has error'}" CommandParameter="tb_dazhebilvamount" ></intr:InvokeCommandAction></intr:EventTrigger><intr:EventTrigger EventName="GotFocus"><intr:InvokeCommandAction Command="{Binding txt_GotFocus}"></intr:InvokeCommandAction></intr:EventTrigger><intr:EventTrigger EventName="LostFocus"><intr:InvokeCommandAction Command="{Binding txt_LostFocus}"></intr:InvokeCommandAction></intr:EventTrigger></intr:Interaction.Triggers></TextBox>      <Button x:Name="btnLogin" Content="登  录" Width="100" FontSize="20" Margin="10" Style="{StaticResource btnOK}"><i:Interaction.Triggers><i:EventTrigger EventName="Click"><i:InvokeCommandAction Command="{Binding btnLogin}"/></i:EventTrigger></i:Interaction.Triggers></Button>  </Grid>
</Window>

个人记录，介绍并不完善,只有几个使用案例，仅供参考。