属性通知之INotifyPropertyChanged

 1   /// <summary>
 2     /// 实体基类，实现了属性通知
 3     /// </summary>
 4     public class BaseEntity : INotifyPropertyChanged
 5     {
 6         public event PropertyChangedEventHandler PropertyChanged;
 7 
 8         /// <summary>
 9         /// 触发属性通知
10         /// 这里用了一个特性的小技巧，就是CallMemberName
11         /// 通过反射来获取调用者的名称，从而避免每一次调用方法都需要将属性名称传入方法
12         /// </summary>
13         /// <param name="propertyName"></param>
14         [NotifyPropertyChangedInvocator]
15         protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
16         {
17             var handler = PropertyChanged;
18             if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
19         }
20     }

 1     /// <summary>
 2     /// 学生类
 3     /// </summary>
 4     public class Student : BaseEntity
 5     {
 6         private string _name;
 7 
 8         /// <summary>
 9         /// 名字
10         /// </summary>
11         public string Name
12         {
13             get { return _name; }
14             set
15             {
16                 _name = value;
17                 OnPropertyChanged();
18             }
19         }
20 
21         private int _age;
22 
23         /// <summary>
24         /// 年龄
25         /// </summary>
26         public int Age
27         {
28             get { return _age; }
29             set
30             {
31                 _age = value;
32                 OnPropertyChanged();
33             }
34         }
35 
36         private double _score;
37 
38         /// <summary>
39         /// 分数
40         /// </summary>
41         public double Score
42         {
43             get { return _score; }
44             set
45             {
46                 _score = value;
47                 OnPropertyChanged();
48             }
49         }
50     }

  public class MainWindowViewModel
    {
        public Student LiLei { get; set; }

        public MainWindowViewModel()
        {
            InitStudentInfo();
            StartUpdateScore();
        }

        //初始化学生信息
        private void InitStudentInfo()
        {
            LiLei = new Student
            {
                Name = "李雷",
                Age = 14,
                Score = 91.5
            };
        }

        //开始更新分数
        private void StartUpdateScore()
        {
            //定义一个定时器，改变分数值，若小于100分，那么增加，否则将到达一个特定分数
            var timer = new DispatcherTimer { Interval = TimeSpan.FromSeconds(1) };
            timer.Tick += (sender, e) =>
            {
                if (LiLei.Score < 99)
                {
                    LiLei.Score++;
                }
                else
                {
                    LiLei.Score = 89.5;
                }
            };
            timer.Start();
        }
    }

 1  <Grid>
 2         <StackPanel>
 3             <TextBlock>
 4                 <Run Text="姓名："/>
 5                 <Run Text="{Binding LiLei.Name}"/>
 6             </TextBlock>
 7             <TextBlock>
 8                 <Run Text="年龄："/>
 9                 <Run Text="{Binding LiLei.Age}"/>
10             </TextBlock>
11             <TextBlock>
12                 <Run Text="分数："/>
13                 <Run Text="{Binding LiLei.Score}"/>
14             </TextBlock>
15         </StackPanel>
16     </Grid>

1     public MainWindow()
2         {
3             InitializeComponent();
4             this.DataContext = new MainWindowViewModel();
5         }