Question

我有以下类来定义附加属性以设置子边距：

public class MarginSetter
{
    public static Thickness GetMargin(DependencyObject obj)
    {
        return (Thickness)obj.GetValue(MarginProperty);
    }

    public static void SetMargin(DependencyObject obj, Thickness value)
    {
        obj.SetValue(MarginProperty, value);
    }

    public static readonly DependencyProperty MarginProperty =
        DependencyProperty.RegisterAttached("Margin", typeof(Thickness), typeof(MarginSetter), new UIPropertyMetadata(new Thickness(), CreateThicknesForChildren));

    public static void CreateThicknesForChildren(object sender, DependencyPropertyChangedEventArgs e)
    {
        var panel = sender as Panel;
        if (panel == null) return;
        foreach (var child in panel.Children)
        {
            var fe = child as FrameworkElement;
            if (fe == null) continue;
            fe.Margin = MarginSetter.GetMargin(panel);
        }
    }
}

问题是，当调用CreateThicknesForChildren时，尚未向父级添加子控件。如何修复这个类，以便它能正确设置所有子控件的边距？

在我的项目中，没有控件被动态添加到父级，它们都是在xaml文件中创建的。顺便说一句，设计师正确地工作，并以某种方式正确设置所有子元素的边距。

Answer 1

如何注册面板的Loaded事件？如果您以后动态添加项目将无济于事，但对于基本的95％，它将起作用：

public static void CreateThicknesForChildren(object sender, DependencyPropertyChangedEventArgs e)
{
    var panel = sender as Panel;
    panel.Loaded += ...
}

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1 个答案: