using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApp13
{
class Program
{
public class Subscriber
{
public static void Main()
{
Publisher publisher = new Publisher();
publisher.BeginAdd += AddCallback;
publisher.EndAdd += EndCallBack;
Console.WriteLine(publisher.Multiply(2.3f, 4.5f));
publisher.BeginAdd -= AddCallback;
publisher.EndAdd -= EndCallBack;
Console.WriteLine(publisher.Multiply(3.3f, 4.4f));
Console.ReadLine();
}
public static void AddCallback(string message)
{
Console.WriteLine("Callback - " + message);
}
public static void EndCallBack(string message)
{
Console.WriteLine("Callback - " + message);
}
}
public class Publisher
{
public delegate void Notify(string message); // Declare delegate.
public event Notify BeginAdd; // Declare event.
public event Notify EndAdd;
public float Multiply(float a, float b)
{
OnBeginAdd(); // Raise event.
OnEndAdd();
return a * b;
}
private void OnBeginAdd()
{
if (BeginAdd != null)
BeginAdd("Starting multiplication!"); // Call callback method.
}
private void OnEndAdd()
{
if (EndAdd != null)
EndAdd("Completing multiplication!");
}
}
}
}
我该如何更正向 Multiply 函数中添加 OnEndAdd() 的语法,以便它只在函数执行完成后回调?我尝试将其添加到 return 语句之后,但显然这不起作用,无法找到其他方法...