WPF - 设置焦点是单击按钮时 - 无code的背后 [英] WPF - Set Focus when a button is clicked - No Code Behind

问题描述

有没有一种方法来设置焦点从一个控件到另一个使用WPF 触发 S'

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

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>

是否有此问题的方法的EventTrigger 将专注于文本框改为txtName？

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

我试图找到做这样的事情采用严格的MVVM的方式。如果这是一件不应该通过XAML（在MVVM）可以做到，那么这是罚款。但我想看到某种文档它是如何适应MVVM模式做了XAML之外。

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

你有没有使用附加的行为考虑。他们是简单的实现和使用AttachedProperty的。虽然它仍然需要code，这code是一类抽象出来，并可以重复使用。他们可以不再需要背后code'和常与MVVM模式使用。

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();
                    }
                };
        }
    }
}

然后在你的XAML做这样的事情...

And then in your XAML do something like...

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

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