WPF 附加属性的使用

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;

namespace Wpf180706
{
    public class School:DependencyObject
    {
        public static int GetGrade(DependencyObject obj)
        {
            return (int)obj.GetValue(GradeProperty);
        }

        public static void SetGrade(DependencyObject obj, int value)
        {
            obj.SetValue(GradeProperty, value);
        }

        // Using a DependencyProperty as the backing store for Grade.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty GradeProperty =
            DependencyProperty.RegisterAttached("Grade", typeof(int), typeof(School), new PropertyMetadata(0)); 
        
    }

}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;

namespace Wpf180706
{
    public class Student:DependencyObject
    {
public static readonly DependencyProperty NameProperty = DependencyProperty.Register("Name",typeof(string),typeof(Student));

    }

}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;

namespace Wpf180706
{
    /// <summary>
    /// Interaction logic for Window1.xaml
    /// </summary>
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
        }

        private void btn_Click(object sender, RoutedEventArgs e)
        {
            Student s = new Student();
            School.SetGrade(s, 5); //设置附加属性
            int grade = School.GetGrade(s);//读取附加属性
            MessageBox.Show(grade.ToString());
        }
    }
}