对象创建的限制 [英] Restriction of object Creation

问题描述

Hi Team，



我想限制用户创建多个对象。我在单身概念中知道这个概念。但是我试图通过以下方式实现。



如果你观察下面的程序我在if循环中抛出异常如果我不抛出异常创建If循环对象，我将能够使用第三个对象访问该方法，即ex3.Display（）;有人可以帮助我如何处理异常，同时对象不会被创建

 使用系统; 
 使用 System.Collections.Generic; 
 使用 System.Linq; 
 使用 System.Text; 
 
 命名空间 ObjectCreation 
 {
  class  ExampleClass 
 {
  public   static   int  classCount =  0 ; 
 
  public  ExampleClass（）
 {
 classCount ++; 
 
  if （classCount >   2 ）
 {
  throw   new 异常（ 对象创建失败 - 对象创建仅限于一个）; 
 
} 
 
  else  
 {
 Console.WriteLine（  Object Created + classCount）; 
} 
} 
 
  public   void 显示（ ）
 {
 Console.WriteLine（ 对象创建）; 
} 
 
 
} 
 
  class 计划
 {
 
 
 静态  void  Main（ string  [] args）
 {
 
 ExampleClass ex1 =  new  ExampleClass（）; 
 ExampleClass ex2 =  new  ExampleClass（）; 
 ExampleClass ex3 =  new  ExampleClass（）; 
 ex3.Display（）; 
 
} 
} 
} 

解决方案

请参阅我对该问题的评论。别担心：模式有很多不好的实现。它通常是微不足道的，但需要考虑一些需要全面考虑的微妙时刻。想看一个好的？这里： http://csharpindepth.com/Articles/General/Singleton.aspx [ ^ ]。

-SA

Hi Team,

I want to restrict user from creating more than 1 object . I know this concept in singleton concept. However I am trying to achieve in the following way.

If you observe the below program i am throwing exception inside the "if loop" if i dont throw the exception inside the "If" loop object gets created and i will be able to access the method using the third object i.e ex3.Display(); Can some one help me how to handle the exception at same time object does not get created

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ObjectCreation
{
    class ExampleClass
    {
        public static int classCount = 0;

        public ExampleClass()
        {
            classCount++;

            if (classCount > 2)
            {
                throw new Exception("Object creation failed - object creation limited only for one");

            }

            else
            {
                Console.WriteLine("Object Created" + classCount);
            }
        }

        public void Display()
        {
            Console.WriteLine("object created");
        }


    }

    class Program
    {


        static void Main(string[] args)
        {

            ExampleClass ex1 = new ExampleClass();
            ExampleClass ex2 = new ExampleClass();
            ExampleClass ex3 = new ExampleClass();
            ex3.Display();

        }
    }
}

解决方案

Please see my comment to the question. Don't worry: there are many bad implementations of the pattern. It's generally trivial, but there are some delicate moments to take into account which require thorough considerations. Want to see a good one? Here: http://csharpindepth.com/Articles/General/Singleton.aspx[^].

—SA

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