WPF - 单击按钮时设置焦点 - 无代码

Question

有没有办法Focus使用WPF从一个控件设置到另一个控件Trigger？

如下例所示:

<Page
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
  <Grid>  
    <Grid.RowDefinitions>
      <RowDefinition/>
      <RowDefinition/>
      <RowDefinition/>
    </Grid.RowDefinitions>

    <TextBox Name="txtName"></TextBox>    
    <TextBox Grid.Row="1" Name="txtAddress"></TextBox>
    <Button Grid.Row="2" Content="Finish">
        <Button.Triggers>
            <EventTrigger RoutedEvent="Button.Click">

                <!-- Insert cool code here-->  

            </EventTrigger>
        </Button.Triggers>
    </Button>
  </Grid>
</Page>

有没有办法EventTrigger把重点放在textBox"txtName"上？

我试图找到使用严格的MVVM做这样的事情的方法.如果这是不应该通过XAML(在MVVM中)完成的,那么这很好.但我希望看到一些文档,说明它如何适合在XAML之外的MVVM模式.

Answer 1

您是否考虑过使用附加行为？它们易于实现并使用AttachedProperty.虽然它仍然需要代码,但是这个代码在类中被抽象出来并被重用.它们可以消除"后面的代码"的需要,并且经常与MVVM模式一起使用.

试试这个,看看它是否适合你.

public class EventFocusAttachment
{
    public static Control GetElementToFocus(Button button)
    {
        return (Control)button.GetValue(ElementToFocusProperty);
    }

    public static void SetElementToFocus(Button button, Control value)
    {
        button.SetValue(ElementToFocusProperty, value);
    }

    public static readonly DependencyProperty ElementToFocusProperty =
        DependencyProperty.RegisterAttached("ElementToFocus", typeof(Control), 
        typeof(EventFocusAttachment), new UIPropertyMetadata(null, ElementToFocusPropertyChanged));

    public static void ElementToFocusPropertyChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
    {
        var button = sender as Button;
        if (button != null)
        {
            button.Click += (s, args) =>
                {
                    Control control = GetElementToFocus(button);
                    if (control != null)
                    {
                        control.Focus();
                    }
                };
        }
    }
}

然后在你的XAML做类似......

<Button 
    Content="Click Me!" 
    local:EventFocusAttachment.ElementToFocus="{Binding ElementName=textBox}" 
    />
<TextBox x:Name="textBox" />

Answer 2

我不在视觉工作室附近所以我现在不能尝试这个,但是在我的头脑中,你应该能够做到这样的事情:

FocusManager.FocusedElement="{Binding ElementName=txtName}">

编辑:

这里有一个关于此的后续问题(最近询问):如何仅在xaml中设置自动对焦？其中包含此方法,以及如何使用它的一些不同的想法.

Answer 3

你也可以使用WPF行为......

    public class FocusElementAfterClickBehavior : Behavior<ButtonBase>
{
    private ButtonBase _AssociatedButton;

    protected override void OnAttached()
    {
        _AssociatedButton = AssociatedObject;

        _AssociatedButton.Click += AssociatedButtonClick;
    }

    protected override void OnDetaching()
    {
        _AssociatedButton.Click -= AssociatedButtonClick;
    }

    void AssociatedButtonClick(object sender, RoutedEventArgs e)
    {
        Keyboard.Focus(FocusElement);
    }

    public Control FocusElement
    {
        get { return (Control)GetValue(FocusElementProperty); }
        set { SetValue(FocusElementProperty, value); }
    }

    // Using a DependencyProperty as the backing store for FocusElement.  This enables animation, styling, binding, etc...
    public static readonly DependencyProperty FocusElementProperty =
        DependencyProperty.Register("FocusElement", typeof(Control), typeof(FocusElementAfterClickBehavior), new UIPropertyMetadata());
}

以下是使用该行为的XAML.

包含名称空间:

xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity" 
xmlns:local="clr-namespace:WpfApplication1"

将WPF行为附加到按钮并将要设置焦点的元素绑定到:

<Button Content="Focus" Width="75">
    <i:Interaction.Behaviors>
        <local:FocusElementAfterClickBehavior FocusElement="{Binding ElementName=CheckBoxComboBox, Mode=OneWay}"/>
    </i:Interaction.Behaviors>
</Button>
<ComboBox x:Name="CheckBoxComboBox" HorizontalAlignment="Center" VerticalAlignment="Center" Width="120" Grid.Row="1"/>

所以这样你就没有代码了,它可以重用于从ButtonBase继承的任何控件.

希望这有助于某人.