C#中如何定义和使用一个自定义事件(2)

在上一个示例中，使用.NET 自定义的委托定义定义事件，不使用自定义委托。

（1） 事件发布者

使用系统的委托EventHandler 定义事件，目前事件不包含参数。

public class EmployeeSeparator
    {
        public event EventHandler EmployeeSeparatored;
        public void Separate()
        {
            EmployeeSeparatored?.Invoke(this,EventArgs.Empty);
        }
    }

事件包含2和参数：object sender， EventArgs e

（2） 事件订阅者

例如，财务部类，使用系统自定义的委托，方法必须和委托一致，所以带有Object参数和EventArgs参数

public class Finance
    {

        private readonly EmployeeSeparator employeeSeparator;
        public Finance(EmployeeSeparator employee)
        {

            this.employeeSeparator = employee;
            employeeSeparator.EmployeeSeparatored += EmployeeSeparator\_EmployeeSeparatored;

        }

        private void EmployeeSeparator_EmployeeSeparatored(object sender, EventArgs e)
        {
            Console.WriteLine("Finance department: employee separetion process related to Finance department. ");

        }
    }

IT部门，通样的方式，订阅事件

public class IT
    {

        private readonly EmployeeSeparator employeeSeparator;
        public IT(EmployeeSeparator employee)
        {

            this.employeeSeparator = employee;
            employeeSeparator.EmployeeSeparatored += EmployeeSeparator\_EmployeeSeparatored;

        }

        private void EmployeeSeparator\_EmployeeSeparatored(object sender, EventArgs e)
        {
            Console.WriteLine("IT department: employee separetion process related to IT department. ");

        }

    }

（3）执行事件

class Program
    {

        static void Main(string[] args)
        {

            EmployeeSeparator employeeSeparator=new EmployeeSeparator();
            Finance finance=new Finance(employeeSeparator);

            IT it = new IT(employeeSeparator);
            employeeSeparator.Separate();
            Console.ReadKey();

        }

    }

执行效果如下：

Finance department: employee separetion process related to Finance department.

IT department: employee separetion process related to IT department.