模拟实现WPF的依赖属性及绑定通知机制（4）--模拟实现绑定连动机

1、一个依赖对象示例：

?public class MyDendencyControl : MyDependencyObject
??? {
??????? public static readonly MyDependencyProperty ContentDependencyProperty =
??????????? MyDependencyProperty.Register("Content",typeof(string),typeof(MyDendencyControl),new MyPropertyMetadata("hello"));

????????//封装成普通属性的依赖属性，注意调用的是基类的相关方法。
??????? public string Content
??????? {
??????????? get
??????????? {
??????????????? return base.GetValue(ContentDependencyProperty).ToString();
??????????? }
??????????? set
??????????? {
??????????????? base.SetValue(ContentDependencyProperty,value);
??????????? }
??????? }
??? }

2）一个实现了INotifyPropertyChanged接口的数据提供类
??? public class MyNotifyPropertyClass : INotifyPropertyChanged
??? {
??????? public event PropertyChangedEventHandler PropertyChanged;
??????? private void RaisePropertyChanged(string PropertyName)
??????? {
??????????? if (PropertyChanged != null)
??????????? {
??????????????? PropertyChanged(this,new PropertyChangedEventArgs(PropertyName));
??????????? }
??????? }
??????? private string _Name;
??????? public string Name
??????? {
??????????? get
??????????? {
??????????????? return _Name;
??????????? }
??????????? set
??????????? {
??????????????? if (_Name != value)?//这是比较好的习惯，可以提供性能.
??????????????? {
??????????????????? _Name = value;
??????????????????? RaisePropertyChanged("Name");
??????????????? }
??????????? }
??????? }
??? }

3、测试连动（应用）

//创建一个依赖对象实例
??????????? MyDendencyControl theCtrl = new MyDendencyControl();
??????????? //创建一个绑定目标类
??????????? MyNotifyPropertyClass theClass = new MyNotifyPropertyClass();
??????????? //构建绑定，这种是手工绑定方法，在xaml中设置，最终也会解释成如下代码:
??????????? MyBinding theBinding = new MyBinding();
??????????? theBinding.TargetObject = theClass;
??????????? theBinding.PropertyName = "Name";
??????????? theCtrl.SetBinding(MyDendencyControl.ContentDependencyProperty,theBinding);
??????????? //默认值
??????????? MessageBox.Show(theCtrl.Content);
??????????? theClass.Name = "hello,you are good!";
??????????? //关联属性变化后再看当前值
??????????? MessageBox.Show(theCtrl.Content);
??????????? //依赖属性变化，会通知关联类属性也变化.
??????????? theCtrl.Content = "are you ready?";
??????????? MessageBox.Show(theClass.Name);

到此，微软的WPF依赖属性，绑定和通知属性及相互连动机制就完成了，当然，只是简单的模拟。微软的实现还是要复杂很多，但原理基本如此。