静态对象解除及关联事件的问题

[xoaoz]

public class Employee : System.ComponentModel.INotifyPropertyChanged
{
	private string _name;
	public string Name
	{
		get{return _name;}
		set{if(_name != value){
		_name =value;
		SendPropertyChanged("Name:"+value);
		}}
	}
	public event System.ComponentModel.PropertyChangedEventHandler PropertyChanged;
		protected virtual void SendPropertyChanged(String propertyName)
		{
			if ((this.PropertyChanged != null))
			{
				this.PropertyChanged(this, new System.ComponentModel.PropertyChangedEventArgs(propertyName));
			}
		}
}

public class ClassTest
{	
	public ClassTest()
	{	   
	   Gloal.Em.PropertyChanged -= Employee_PropertyChanged;	
	   Gloal.Em.PropertyChanged += Employee_PropertyChanged;
	}
	private void Employee_PropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
	{
		Console.WriteLine(e.PropertyName);
	}
}

public class Gloal
{
   public static Employee Em;
}

static class Program
{
   [STAThread]
   static void Main(string[] args)
   {
	Gloal.Em = new Employee{Name = "a"};

	ClassTest t = new ClassTest();
	Gloal.Em.Name = "b";
	
	ClassTest t1 = new ClassTest();
	Gloal.Em.Name = "c";
	
	ClassTest t2 = new ClassTest();
	ClassTest t12 = new ClassTest();
	Gloal.Em.Name = "d";
   }
｝

输出结果：
Name:b
Name:c
Name:c
Name:d
Name:d
Name:d
Name:d

-= 为啥不起作用呢?

[bdmh]

Gloal.Em.PropertyChanged -= Employee_PropertyChanged;
Gloal.Em.PropertyChanged += Employee_PropertyChanged;
你减完了，又加上了

[ohkuy]

SendPropertyChanged("Name:"+value);
改为：
SendPropertyChanged("Name:");
试试~~

[xoaoz]

减完了，又加上了，就是想确保只关联一次。

Gloal.Em.Name = "d"的时候，触发了4次!

[xboxeer]

public ClassTest()
    {       
       Gloal.Em.PropertyChanged -= Employee_PropertyChanged;    
       Gloal.Em.PropertyChanged += Employee_PropertyChanged;
    }
    private void Employee_PropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
    {
        Console.WriteLine(e.PropertyName);
    }

=》

 public ClassTest()
        {
            
            Gloal.Em.PropertyChanged += Employee_PropertyChanged;
        }
        private void Employee_PropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
        {
            Console.WriteLine(e.PropertyName);
            Gloal.Em.PropertyChanged -= Employee_PropertyChanged;
        }

说实话这样子在一个实例构造函数里面去改变一个静态变量 我觉得出问题很正常~