DependencyProperty使用中的3个场景，讨论PropertyChangedCallback

1：项目结构图

2：控件SilverlightControl1

前台：

后台：

    public partial class SilverlightControl1 : UserControl

    {

        public SilverlightControl1()

        {

            InitializeComponent();

        }



        public static readonly DependencyProperty StudentProperty = DependencyProperty.Register("Student", typeof(Student), typeof(SilverlightControl1), new PropertyMetadata(new PropertyChangedCallback(xxx)));



        public Student Student

        {

            get

            {

                return (Student)GetValue(StudentProperty);

            }

            set

            {

                SetValue(StudentProperty, value);

                

            }

        }



        static void xxx(DependencyObject d, DependencyPropertyChangedEventArgs e)

        {

            MessageBox.Show("sss");

        }

    }

3：调用方

前台：

后台：

    public partial class MainPage : UserControl

    {

        public MainPage()

        {

            InitializeComponent();

        }



        Student student1 = new Student() { StudentName = "hzh" + DateTime.Now.ToFileTime(), Age = 99 };

        Student student2 = new Student() { StudentName = "lmj" + DateTime.Now.ToFileTime(), Age = 99 };

        Student student3 = new Student() { StudentName = "lh" + DateTime.Now.ToFileTime(), Age = 99 };



        //初始化

        private void Button_Click(object sender, RoutedEventArgs e)

        {

            //采用非绑定机制

            uc1.Student = student1;

            //采用非绑定机制，对DataContext赋值

            uc2.DataContext = student2;

            //采用绑定机制

            uc3.DataContext = student3;

        }



        //改Model值

        private void Button_Click1(object sender, RoutedEventArgs e)

        {

            student1.StudentName = "lmj" + DateTime.Now.ToString();

            student1.Age = 90;

            student2.StudentName = "hzh" + DateTime.Now.ToString();

            student2.Age = 90;

            student3.StudentName = "hzh" + DateTime.Now.ToString();

            student3.Age = 90;

        }



        //更换Model

        private void Button_Click_1(object sender, RoutedEventArgs e)

        {

            student1 = new Student() { StudentName = "hzh" + DateTime.Now.ToFileTime(), Age = 99 };

            student2 = new Student() { StudentName = "lmj" + DateTime.Now.ToFileTime(), Age = 99 };

            student3 = new Student() { StudentName = "lh" + DateTime.Now.ToFileTime(), Age = 99 };

        }

    }

4：结论

无论是第一种方式，还是第三种方式，都能触发PropertyChangedCallback，而如果调用采用第二种方式，则不会触发PropertyChangedCallback。

源码：SilverlightApplication320110609.rar