C#构造函数事件

Question

我创建了一个类,当我通过表单创建一个员工对象时,我想给出一个消息;

这是我的班级,活动和代表

public delegate void ctorDel(); 

class Employee
{
    private int empID;
    private string empName;

    public event ctorDel myEvent;

    public Employee(int empID,string empName)
    {
        this.empID = empID;
        this.empName = empName;

        **if (myEvent != null)
        {
            myEvent();
        }**
    }

并以形式

  int id = Convert.ToInt16(textBox1.Text);
            string name = textBox2.Text;

            Employee emp = new Employee(id, name);
            emp.myEvent += new ctorDel(showMessage);

和功能

 public void showMessage()
        {
            MessageBox.Show("An employee is created");
        }

Answer 1

您在构造函数已经运行后附加事件.

Answer 2

你想要完成的是什么？您尝试过的原因不起作用是因为您在ctor之后附加了您的代表.一旦你打电话给"新员工",事件就会被解雇.

如果您确实需要这样的事件,请创建一个工厂类:

public delegate void EmpCreated();
public EmployeeFactory {
  public event EmpCreated myEvent;
  public Employee Create(int empId, string empName){
    var result = new Employee(empId, empName);
    if(myEvent != null) myEvent();
    return result;
  }
}

订阅工厂类的活动,您将获得活动.