WPF - 单击按钮时设置焦点 - 无代码隐藏 [英] WPF - Set Focus when a button is clicked - No Code Behind

问题描述

有没有办法使用 WPF Triggers 将 Focus 从一个控件设置到另一个控件?

Is there a way to set Focus from one control to another using WPF Triggers?

就像下面的例子:

<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>

有没有办法让这个 EventTrigger 把焦点放在文本框txtName"上?

Is there a way for this EventTrigger to put to focus on the textBox "txtName"?

我正在尝试使用严格的 MVVM 找到执行此类操作的方法.如果这是不应该通过 XAML(在 MVVM 中)完成的事情，那很好.但我想查看一些关于它如何在 XAML 之外执行它的 MVVM 模式的文档.

I am trying to find the way to do something like this using strict MVVM. If this is something that should not be done via the XAML (in MVVM) then that is fine. But I would like to see some kind of documentation as to how it fit in the MVVM pattern doing it outside the XAML.

推荐答案

您是否考虑过使用附加行为.它们易于实现和使用 AttachedProperty.虽然它仍然需要代码，但这些代码在一个类中被抽象出来并被重用.它们可以消除代码隐藏"的需要，并且经常与 MVVM 模式一起使用.

Have you considered using an attached behaviour. They are simple to implement and use AttachedProperty's. Although it still requires code, this code is abstracted away in a class and be reused. They can eliminate the need 'code behind' and are often used with the MVVM pattern.

试试这个，看看它是否适合你.

Try this one and see if it works for you.

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();
                    }
                };
        }
    }
}

然后在您的 XAML 中执行类似...

And then in your XAML do something like...

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

这篇关于WPF - 单击按钮时设置焦点 - 无代码隐藏的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！