通过 INotifyPropertyChanged 实现观察者模式

INotifyPropertyChanged

它的作用:向客户端发出某一属性值已更改的通知。

当属性改变时,它可以通知客户端,并进行界面数据更新.而我们不用写很多复杂的代码来更新界面数据,这样可以做到方法简洁而清晰,松耦合和让方法变得更通用.可用的地方太多了:例如上传进度,实时后台数据变更等地方。

它的作用:向客户端发出某一属性值已更改的通知。

当属性改变时,它可以通知客户端,并进行界面数据更新.而我们不用写很多复杂的代码来更新界面数据,这样可以做到方法简洁而清晰,松耦合和让方法变得更通用.可用的地方太多了:例如上传进度,实时后台数据变更等地方.目前我发现winform和silverlight都支持,确实是一个强大的接口.

在构造函数中先绑定

, );
        }

].CustomerName = ].PhoneNumber = , );
        }

].CustomerName = ].PhoneNumber = "(708)555-0150";

//如果数据源是换成List<T>只有刷新以后才能即使更新。
            this.customersDataGridView.Refresh();
        }

private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
        {

}

}

// This is a simple customer class that 
    // implements the IPropertyChange interface.
    public class DemoCustomer : INotifyPropertyChanged
    {
        // These fields hold the values for the public properties.
        private Guid idValue = Guid.NewGuid();
        private string customerNameValue = String.Empty;
        private string phoneNumberValue = String.Empty;

public event PropertyChangedEventHandler PropertyChanged;

private void NotifyPropertyChanged(String info)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(info));
            }
        }

// The constructor is private to enforce the factory pattern.
        private DemoCustomer()
        {
            customerNameValue = "Customer";
            phoneNumberValue = "(555)555-5555";
        }

// This is the public factory method.
        public static DemoCustomer CreateNewCustomer()
        {
            return new DemoCustomer();
        }

// This property represents an ID, suitable
        // for use as a primary key in a database.
        public Guid ID
        {
            get
            {
                return this.idValue;
            }
        }

public string CustomerName
        {
            get
            {
                return this.customerNameValue;
            }

set
            {
                if (value != this.customerNameValue)
                {
                    this.customerNameValue = value;
                    NotifyPropertyChanged("CustomerName");
                }
            }
        }

public string PhoneNumber
        {
            get
            {
                return this.phoneNumberValue;
            }

set
            {
                if (value != this.phoneNumberValue)
                {
                    this.phoneNumberValue = value;
                    NotifyPropertyChanged("PhoneNumber");
                }
            }
        }
    }

（3）、让INotifyPropertyChanged的实现更优雅一些http://tech.ddvip.com/2009-05/1242645380119734_2.html

很好，很强大，高端大气上档次

public class DemoCustomer1 : PropertyChangedBase
    {
        // These fields hold the values for the public properties.
        private Guid idValue = Guid.NewGuid();
        private string customerNameValue = String.Empty;
        private string phoneNumberValue = String.Empty;

// The constructor is private to enforce the factory pattern.
        private DemoCustomer1()
        {
            customerNameValue = "Customer";
            phoneNumberValue = "(555)555-5555";
        }

// This is the public factory method.
        public static DemoCustomer1 CreateNewCustomer()
        {
            return new DemoCustomer1();
        }

// This property represents an ID, suitable
        // for use as a primary key in a database.
        public Guid ID
        {
            get
            {
                return this.idValue;
            }
        }

public string CustomerName
        {
            get
            {
                return this.customerNameValue;
            }

set
            {
                if (value != this.customerNameValue)
                {
                    this.customerNameValue = value;
                    this.NotifyPropertyChanged(p => p.CustomerName);
                    //NotifyPropertyChanged("CustomerName");
                }
            }
        }

public string PhoneNumber
        {
            get
            {
                return this.phoneNumberValue;
            }

set
            {
                if (value != this.phoneNumberValue)
                {
                    this.phoneNumberValue = value;
                    this.NotifyPropertyChanged(p => p.PhoneNumber);
                    //NotifyPropertyChanged("PhoneNumber");
                }
            }
        }
    }

/// <summary>
    /// 基类
    /// </summary>
    public class PropertyChangedBase : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;

public void NotifyPropertyChanged(string propertyName)
        {
            if (this.PropertyChanged != null)
            {
                this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }
    }

/// <summary>
    /// 扩展方法
    /// </summary>
    public static class PropertyChangedBaseEx
    {
        public static void NotifyPropertyChanged<T, TProperty>(this　T propertyChangedBase, Expression<Func<T, TProperty>> expression) where T : PropertyChangedBase
        {
            var memberExpression = expression.Body as MemberExpression;
            if (memberExpression != null)
            {
                string propertyName = memberExpression.Member.Name;
                propertyChangedBase.NotifyPropertyChanged(propertyName);
            }
            else
                throw new NotImplementedException();
        }
    }View Code