[英]WPF and MVVM : How to move focus to the next Control automatically
I have a little WPF Window with 2 TextBoxes Having Ordered TabIndex 0,1 and i want to move focus automatically from the first TextBox to the second when i press Enter Key. 我有一个带有2个TextBoxes的WPF窗口,它有Ordered TabIndex 0,1我希望在按Enter键时自动将焦点从第一个TextBox移动到第二个TextBox。 I Use MVVM Light. 我使用MVVM Light。
Remark : This post is not duplicated. 备注:这篇文章不重复。 here I do not use Classic approach with event Handler but MVVM Pattern and as you know Code Behind is not allowed in view. 在这里,我不使用事件处理程序的经典方法,但MVVM模式,因为你知道在视图中不允许使用Code Behind。
I Found a solution but I don't know if it respect MVVM Principle. 我找到了解决方案,但我不知道它是否尊重MVVM原则。 Here the code : 这里的代码:
The View 风景
<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>
The ViewModel : 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);
}
}
}
I don't know if use of "Control" Class in ViewModel Is allowed or not 我不知道是否允许在ViewModel中使用“Control”类
As you are using MVVM, you can use a Behavior for this: 当您使用MVVM时,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;
}
}
In your xaml: 在你的xaml中:
<TextBox>
<i:Interaction.Behaviors>
<wpfTest:TabOnEnterBehavior />
</i:Interaction.Behaviors>
</TextBox>
Add a PreviewKeyDown
event to your TextBox
first: 首先在TextBox
添加一个PreviewKeyDown
事件:
<TextBox PreviewKeyDown="OnTextBoxKeyDown" />
Then create a TraversalRequest
to move focus to the next item: 然后创建一个TraversalRequest
以将焦点移动到下一个项目:
private void OnTextBoxKeyDown(object sender, KeyEventArgs e)
{
if (e.Key == Key.Return)
{
TraversalRequest request = new TraversalRequest(FocusNavigationDirection.Next);
MoveFocus(request);
}
}
EDIT 编辑
Alternatively, if you prefer using a Command, you can just set a KeyBinding
in your TextBox
: 或者,如果您更喜欢使用Command,则可以在TextBox
设置KeyBinding
:
<TextBox.InputBindings>
<KeyBinding Key="Enter" Command="{Binding YourCommand}" />
</TextBox.InputBindings>
And just put pretty much the same thing as above in your ICommand s
Execute` logic. 并且在ICommand s
Execute`逻辑中添加与上面相同s
内容。
Also, same question here: How do I simulate a Tab key press when Return is pressed in a WPF application? 此外,同样的问题: 如何在WPF应用程序中按下Return键时模拟Tab键按下?
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