Question

我有一个带有2个TextBox的Orve TabIndex 0,1的WPF窗口，我想在按Enter键时自动将焦点从第一个TextBox移动到第二个TextBox。我使用MVVM Light。

备注：此帖子不重复。这里我不使用事件处理程序的经典方法，而是使用MVVM模式，因为你知道在视图中不允许使用Code Behind。

我找到了解决方案，但我不知道它是否尊重MVVM原则。代码如下：

视图

<Window x:Class="WpfMMVLight2.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
    xmlns:cmd ="http://www.galasoft.ch/mvvmlight"
    Title="MainWindow" Height="350" Width="525"
    DataContext="{Binding MainViewModel}">
    <Grid FocusManager.FocusedElement="{Binding ElementName=tb1}">
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="Auto"/>
        <ColumnDefinition Width="70"/>
    </Grid.ColumnDefinitions>

    <Grid.RowDefinitions>
        <RowDefinition Height="Auto"/>
        <RowDefinition Height="Auto"/>
    </Grid.RowDefinitions>

    <TextBlock Grid.Column="0" Text="Text 1" VerticalAlignment="Center"/>
    <TextBox x:Name="tb1" Grid.Column="1" VerticalAlignment="Center" Margin="5">
        <i:Interaction.Triggers>
            <i:EventTrigger EventName="KeyDown">
                <cmd:EventToCommand PassEventArgsToCommand="True"
                Command ="{Binding KeyDownCommand, Mode=OneWay}"/>
            </i:EventTrigger>
        </i:Interaction.Triggers>
    </TextBox>


     <TextBlock Grid.Column="0" Grid.Row="1" Text="Text 2" VerticalAlignment="Center"/>
     <TextBox x:Name="tb2" Grid.Column="1" Grid.Row="1" VerticalAlignment="Center" Margin="5">
        <i:Interaction.Triggers>
            <i:EventTrigger EventName="KeyDown">
                <cmd:EventToCommand PassEventArgsToCommand="True"
            Command ="{Binding KeyDownCommand, Mode=OneWay}"/>
            </i:EventTrigger>
        </i:Interaction.Triggers>
    </TextBox>

</Grid>

ViewModel：

 private ICommand _keydownCommand;
 public ICommand KeyDownCommand
    {
       get
        {
            if (_keydownCommand== null)
                _keydownCommand= new DelegateCommand<KeyEventArgs>(KeyDownCommandExecute);
            return _keydownCommand;
        }



    }


    private void KeyDownCommandExecute(KeyEventArgs e)
    {
        if (e != null && e.Key == Key.Enter)
        {
      TraversalRequest request = new TraversalRequest(FocusNavigationDirection.Next);
      request.Wrapped = true;
      ((Control)e.Source).MoveFocus(request);
     }
    }
}

我不知道是否允许在ViewModel中使用“Control”类

Answer 1

在使用MVVM时，您可以使用行为：

public class TabOnEnterBehavior : Behavior<TextBox>
{

  protected override void OnAttached()
  {
    AssociatedObject.PreviewKeyDown += AssociatedObject_PreviewKeyDown;
  }

  private void AssociatedObject_PreviewKeyDown(object sender, KeyEventArgs e)
  {
    if (e.Key == Key.Enter)
    {
      var request = new TraversalRequest(FocusNavigationDirection.Next);
      request.Wrapped = true;
      AssociatedObject.MoveFocus(request);
    }
  }

  protected override void OnDetaching()
  {
    AssociatedObject.PreviewKeyDown -= AssociatedObject_PreviewKeyDown;
  }

}

在你的xaml中：

<TextBox>
  <i:Interaction.Behaviors>
    <wpfTest:TabOnEnterBehavior />
  </i:Interaction.Behaviors>
</TextBox>

Answer 2

首先向PreviewKeyDown添加TextBox个活动：

<TextBox PreviewKeyDown="OnTextBoxKeyDown" />

然后创建TraversalRequest以将焦点移至下一个项目：

private void OnTextBoxKeyDown(object sender, KeyEventArgs e)
{
 if (e.Key == Key.Return)
 {
   TraversalRequest request = new TraversalRequest(FocusNavigationDirection.Next);
   MoveFocus(request);
 }
}

修改

或者，如果您更喜欢使用命令，则只需在KeyBinding中设置TextBox：

<TextBox.InputBindings> <KeyBinding Key="Enter" Command="{Binding YourCommand}" /> </TextBox.InputBindings>

在ICommand s Execute`逻辑中添加与上面相同的内容。

此外，同样的问题：How do I simulate a Tab key press when Return is pressed in a WPF application?

WPF和MVVM：如何自动将焦点移动到下一个控件

2 个答案: