上输入键preSS绑定文本框 [英] Bind TextBox on Enter-key press

问题描述

在文本框默认绑定为双向，并提交该文本的属性，只有当文本框失去了重心。

The default databinding on TextBox is TwoWay and it commits the text to the property only when TextBox lost its focus.

有没有简单的XAML的方式，使数据绑定发生在我preSS上的文本框回车键？我知道这是pretty的容易做的code落后，但想象一下，如果这个文本框是里面的一些复杂的的DataTemplate 。

Is there any easy XAML way to make the databinding happen when I press the Enter key on the TextBox?. I know it is pretty easy to do in the code behind, but imagine if this TextBox is inside some complex DataTemplate.

推荐答案

您可以自己纯XAML的方式通过创建的附加的行为。

You can make yourself a pure XAML approach by creating an attached behaviour.

事情是这样的：

public static class InputBindingsManager
{

    public static readonly DependencyProperty UpdatePropertySourceWhenEnterPressedProperty = DependencyProperty.RegisterAttached(
            "UpdatePropertySourceWhenEnterPressed", typeof(DependencyProperty), typeof(InputBindingsManager), new PropertyMetadata(null, OnUpdatePropertySourceWhenEnterPressedPropertyChanged));

    static InputBindingsManager()
    {

    }

    public static void SetUpdatePropertySourceWhenEnterPressed(DependencyObject dp, DependencyProperty value)
    {
        dp.SetValue(UpdatePropertySourceWhenEnterPressedProperty, value);
    }

    public static DependencyProperty GetUpdatePropertySourceWhenEnterPressed(DependencyObject dp)
    {
        return (DependencyProperty)dp.GetValue(UpdatePropertySourceWhenEnterPressedProperty);
    }

    private static void OnUpdatePropertySourceWhenEnterPressedPropertyChanged(DependencyObject dp, DependencyPropertyChangedEventArgs e)
    {
        UIElement element = dp as UIElement;

        if (element == null)
        {
            return;
        }

        if (e.OldValue != null)
        {
            element.PreviewKeyDown -= HandlePreviewKeyDown;
        }

        if (e.NewValue != null)
        {
            element.PreviewKeyDown += new KeyEventHandler(HandlePreviewKeyDown);
        }
    }

    static void HandlePreviewKeyDown(object sender, KeyEventArgs e)
    {
        if (e.Key == Key.Enter)
        {
            DoUpdateSource(e.Source);
        }
    }

    static void DoUpdateSource(object source)
    {
        DependencyProperty property =
            GetUpdatePropertySourceWhenEnterPressed(source as DependencyObject);

        if (property == null)
        {
            return;
        }

        UIElement elt = source as UIElement;

        if (elt == null)
        {
            return;
        }

        BindingExpression binding = BindingOperations.GetBindingExpression(elt, property);

        if (binding != null)
        {
            binding.UpdateSource();
        }
    }
}

然后在您的XAML将 InputBindingsManager.UpdatePropertySourceWhenEnter pressedProperty 属性您想更新时，其中一个<大骨节病>输入键pressed。像这样

Then in your XAML you set the InputBindingsManager.UpdatePropertySourceWhenEnterPressedProperty property to the one you want updating when the Enter key is pressed. Like this

<TextBox Name="itemNameTextBox"
         Text="{Binding Path=ItemName, UpdateSourceTrigger=PropertyChanged}"
         b:InputBindingsManager.UpdatePropertySourceWhenEnterPressed="TextBox.Text"/>

（你只需要确保在您的XAML文件指向其中的根元素包括B了xmlns CLR命名空间参考以往命名空间你把InputBindingsManager中）。

(You just need to make sure to include an xmlns clr-namespace reference for "b" in the root element of your XAML file pointing to which ever namespace you put the InputBindingsManager in).

这篇关于上输入键preSS绑定文本框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！