C# 如何使附加属性对子集合更改作出反应?
我有以下类定义附加属性以设置子级边距:C# 如何使附加属性对子集合更改作出反应?,c#,wpf,xaml,C#,Wpf,Xaml,我有以下类定义附加属性以设置子级边距: public class MarginSetter { public static Thickness GetMargin(DependencyObject obj) { return (Thickness)obj.GetValue(MarginProperty); } public static void SetMargin(DependencyObject obj, Thickness value)
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,调用CreateThecknesForChildren时,尚未将任何子控件添加到父控件。如何修复该类,以便正确设置所有子控件的边距
在我的项目中,没有控件动态添加到父级,它们都是在xaml文件中创建的。顺便说一句,设计器工作正常,并且以某种方式为所有子元素正确设置了边距。注册到面板的已加载事件如何?如果您以后动态添加项目,这将没有帮助,但对于基本的95%,这将起作用:
public static void CreateThicknesForChildren(object sender, DependencyPropertyChangedEventArgs e)
{
var panel = sender as Panel;
panel.Loaded += ...
}