设计模式之美：Dynamic Property（动态属性）

  1 namespace DynamicPropertyPattern.Implementation1
  2 {
  3   public class Person
  4   {
  5     private PropertyList _properties = new PropertyList(null);
  6 
  7     public Property GetProperty(string propertyName)
  8     {
  9       return _properties.GetProperty(propertyName);
 10     }
 11 
 12     public bool HasProperty(string propertyName)
 13     {
 14       return _properties.HasProperty(propertyName);
 15     }
 16 
 17     public void AddProperty(string propertyName, Property property)
 18     {
 19       _properties.AddProperty(propertyName, property);
 20     }
 21 
 22     public void RemoveProperty(string propertyName)
 23     {
 24       _properties.RemoveProperty(propertyName);
 25     }
 26 
 27     public IEnumerable<Property> GetAllProperties()
 28     {
 29       return _properties.GetAllProperties();
 30     }
 31   }
 32 
 33   public class Property
 34   {
 35     public string Name { get; set; }
 36     public string Value { get; set; }
 37   }
 38 
 39   public class PropertyList
 40   {
 41     private PropertyList _parent;
 42     private Dictionary<string, Property> _properties
 43       = new Dictionary<string, Property>();
 44 
 45     public PropertyList(PropertyList parent)
 46     {
 47       _parent = parent;
 48     }
 49 
 50     public PropertyList Parent
 51     {
 52       get
 53       {
 54         return _parent;
 55       }
 56     }
 57 
 58     public Property GetProperty(string propertyName)
 59     {
 60       if (_properties.ContainsKey(propertyName))
 61         return _properties[propertyName];
 62       if (_parent != null && _parent.HasProperty(propertyName))
 63         return _parent.GetProperty(propertyName);
 64       return null;
 65     }
 66 
 67     public bool HasProperty(string propertyName)
 68     {
 69       return (_properties.ContainsKey(propertyName))
 70         || (_parent != null && _parent.HasProperty(propertyName));
 71     }
 72 
 73     public void AddProperty(string propertyName, Property property)
 74     {
 75       _properties.Add(propertyName, property);
 76     }
 77 
 78     public void RemoveProperty(string propertyName)
 79     {
 80       _properties.Remove(propertyName);
 81     }
 82 
 83     public IEnumerable<Property> GetAllProperties()
 84     {
 85       List<Property> properties = new List<Property>();
 86 
 87       if (_parent != null)
 88         properties.AddRange(_parent.GetAllProperties());
 89 
 90       properties.AddRange(_properties.Values);
 91 
 92       return properties;
 93     }
 94   }
 95 
 96   public class Client
 97   {
 98     public void TestCase1()
 99     {
100       Person dennis = new Person();
101       dennis.AddProperty("Contact", new Property() { Name = "Contact", Value = "Beijing" });
102       dennis.AddProperty("Age", new Property() { Name = "Age", Value = "18" });
103       dennis.AddProperty("Gender", new Property() { Name = "Gender", Value = "Male" });
104 
105       if (dennis.HasProperty("Contact"))
106       {
107         Property property = dennis.GetProperty("Contact");
108       }
109     }
110   }
111 }