绑定未在CommandBinding中执行

Question

我有这个xaml代码：

<Window.CommandBindings>
    <CommandBinding Command="WpfApplication1:MainCommands.Search" Executed="Search"/>
</Window.CommandBindings><Grid>
<StackPanel>
    <ListView ItemsSource="{Binding SearchContext}" />
    <TextBox Text="{Binding LastName}">
        <TextBox.InputBindings>
            <KeyBinding Key="Enter" Command="{x:Static WpfApplication1:MainCommands.Search}" />
        </TextBox.InputBindings>
    </TextBox>
</StackPanel>

Search-Method看起来像这样：

private void Search(object sender, RoutedEventArgs e)
{
    SearchContext = new ObservableCollection<string>(list.Where(element => element.Name == LastName).Select(el => el.Name).ToList());
}

MainCommands：

public static class MainCommands
{
    public static RoutedCommand Search = new RoutedCommand();
}

但是当焦点在textbox中时，如果我按enter，绑定是‘nt computet，LastName是Null。原因何在？我怎样才能避免这种情况？或者可以显式调用绑定操作？

提前谢谢你。

Answer 1

将UpdateSourceTrigger属性设置为PropertyChanged

<TextBox Text="{Binding LastName, UpdateSourceTrigger=PropertyChanged}">

这将导致立即设置源属性(LastName)：https://msdn.microsoft.com/en-us/library/system.windows.data.updatesourcetrigger(v=vs.110).aspx

Answer 2

正如我所看到的，您的Window是它的视图模型。我建议您使用MVVM，并为视图模型提供单独的类，以便在KeyBinding上放置所需的ICommand和使用CommandParameter

<TextBox x:Name="searchBox"
         Text="{Binding LastName}">
    <TextBox.InputBindings>
        <KeyBinding Key="Enter"
                    Command="{Binding Path=SearchCommand}"
                    CommandParameter="{Binding Path=Text, ElementName=searchBox}" />
    </TextBox.InputBindings>
</TextBox>