c# – 将行为附加到Silverlight中的所有TextBox

发布时间：2020-12-15 08:13:40 所属栏目：百科来源：网络整理

导读：是否可以将行为附加到Silverlight应用程序中的所有TextBox？我需要为所有文本框添加简单的功能. (选择焦点事件上的所有文字) void Target_GotFocus(object sender,System.Windows.RoutedEventArgs e) { Target.SelectAll(); } 解决方法您可以覆盖应用中Tex

是否可以将行为附加到Silverlight应用程序中的所有TextBox？

我需要为所有文本框添加简单的功能.
(选择焦点事件上的所有文字)

void Target_GotFocus(object sender,System.Windows.RoutedEventArgs e)
    {
        Target.SelectAll();
    }

解决方法

您可以覆盖应用中TextBoxes的默认样式.然后在这种风格中,您可以使用某种方法将行为应用于setter(通常使用附加属性).

它会是这样的：

<Application.Resources>
    <Style TargetType="TextBox">
        <Setter Property="local:TextBoxEx.SelectAllOnFocus" Value="True"/>
    </Style>
</Application.Resources>

行为实现：

public class TextBoxSelectAllOnFocusBehavior : Behavior<TextBox>
{
    protected override void OnAttached()
    {
        base.OnAttached();

        this.AssociatedObject.GotMouseCapture += this.OnGotFocus;
        this.AssociatedObject.GotKeyboardFocus += this.OnGotFocus;
    }

    protected override void OnDetaching()
    {
        base.OnDetaching();

        this.AssociatedObject.GotMouseCapture -= this.OnGotFocus;
        this.AssociatedObject.GotKeyboardFocus -= this.OnGotFocus;
    }

    public void OnGotFocus(object sender,EventArgs args)
    {
        this.AssociatedObject.SelectAll();
    }
}

附加属性可以帮助我们应用这些行为：

public static class TextBoxEx
{
    public static bool GetSelectAllOnFocus(DependencyObject obj)
    {
        return (bool)obj.GetValue(SelectAllOnFocusProperty);
    }
    public static void SetSelectAllOnFocus(DependencyObject obj,bool value)
    {
        obj.SetValue(SelectAllOnFocusProperty,value);
    }
    public static readonly DependencyProperty SelectAllOnFocusProperty =
        DependencyProperty.RegisterAttached("SelectAllOnFocus",typeof(bool),typeof(TextBoxSelectAllOnFocusBehaviorExtension),new PropertyMetadata(false,OnSelectAllOnFocusChanged));


    private static void OnSelectAllOnFocusChanged(DependencyObject sender,DependencyPropertyChangedEventArgs args)
    {
        var behaviors = Interaction.GetBehaviors(sender);

        // Remove the existing behavior instances
        foreach (var old in behaviors.OfType<TextBoxSelectAllOnFocusBehavior>().ToArray())
            behaviors.Remove(old);

        if ((bool)args.NewValue)
        {
            // Creates a new behavior and attaches to the target
            var behavior = new TextBoxSelectAllOnFocusBehavior();

            // Apply the behavior
            behaviors.Add(behavior);
        }
    }
}

（编辑：李大同）

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