LostFocus 绑定缺少 setter 调用

Question

我在 TextBox 上遇到双向 Binding 的问题。

<TextBox Text="{Binding Path=MyText, Mode="TwoWay", UpdateSourceTrigger=LostFocus}" />

在离开此元素的焦点时，我希望 setter 调用 MyText，即使 Text 属性没有改变。

public string MyText {
    get { return _myText; }
    set {
        if (value == _myText) {
            RefreshOnValueNotChanged();
            return;
        }
        _myText = value;
        NotifyOfPropertyChange(() => MyText);
    }
}

从未调用测试函数RefreshOnValueNotChanged()。有人知道诀窍吗？我需要 UpdateSourceTrigger=LostFocus，因为 Enter 的附加行为（我需要完整的用户输入...）。

<TextBox Text="{Binding Path=MyText, Mode="TwoWay", UpdateSourceTrigger=LostFocus}" >
    <i:Interaction.Behaviors>
        <services2:TextBoxEnterBehaviour />
    </i:Interaction.Behaviors>
</TextBox>

与 class:

public class TextBoxEnterBehaviour : Behavior<TextBox>
{
    #region Private Methods

    protected override void OnAttached()
    {
        if (AssociatedObject != null) {
            base.OnAttached();
            AssociatedObject.PreviewKeyUp += AssociatedObject_PKeyUp;
        }
    }

    protected override void OnDetaching()
    {
        if (AssociatedObject != null) {
            AssociatedObject.PreviewKeyUp -= AssociatedObject_PKeyUp;
            base.OnDetaching();
        }
    }

    private void AssociatedObject_PKeyUp(object sender, KeyEventArgs e)
    {
        if (!(sender is TextBox) || e.Key != Key.Return) return;
        e.Handled = true;
        ((TextBox) sender).MoveFocus(new TraversalRequest(FocusNavigationDirection.Next));
    }

    #endregion
}

Answer 1

我自己找到了解决方法。但也许有人有比这更好的解决方案。现在我操纵 GotFocus 处的值。然后总是在离开控件焦点时调用 setter...

<TextBox Text="{Binding Path=MyText, Mode="TwoWay", UpdateSourceTrigger=LostFocus}" GotFocus="OnGotFocus" >
    <i:Interaction.Behaviors>
        <services2:TextBoxEnterBehaviour />
    </i:Interaction.Behaviors>
</TextBox>

与：

private void OnGotFocus(object sender, RoutedEventArgs e)
{
    var tb = sender as TextBox;
    if(tb == null) return;
    var origText = tb.Text;
    tb.Text += " ";
    tb.Text = origText;
}

LostFocus 绑定缺少 setter 调用

LostFocus Binding missing setter call

data-binding

wpf

setter

updatesourcetrigger