可以用不同的返回类型进行功能过载......？ [英] Can function overload with different return type...?

问题描述

您好我是C＃& amp;的初学者.NET。

在下面的代码中，CreateCountry函数声明为int，它的返回类型也是int（这部分我得到了它）



但我对int函数中重载的字符串变量感到困惑，在这段代码中也没有将给定的字符串转换为int值。



请指导我。谢谢（参考：CRUD项目）

Hi I am a beginner in C# & .NET.
In the following code CreateCountry function declared as int and its return type is also int (this part I got it)

But I am confused about the overloaded string variable in int function, also nowhere in this piece of code the given string is converted to int value.

Please guide me. Thank you (Reference:CRUD project)

public int CreateCountry(string countryName)
{
   if (string.IsNullOrEmpty(countryName))
   {
       return -1;
   }
   else
   {
        DALCountry dalCountry = new DALCountry();
        return dalCountry.CreateCountry(countryName);
   }            
}

推荐答案

检查国家/地区参数并抛出异常是更好的设计不对。调用函数将有一个try / catch块来处理错误。

It would be better design to check the country argument and throw an exception if it's not right. The calling function would have a try/catch block to handle the error.

public DALCountry CreateCountry(string countryName)
{
  if (String.IsNullOrEmpty(countryName))
    throw new ArgumentException("countryName");

  DALCountry dalCountry = new DALCountry();
  return dalCountry.CreateCountry(countryName);
}

你的问题没有多大意义。



您是否询问如何使用具有相同参数类型的副本重载方法，在您的情况下是一个字符串，并且只有返回类型不同？您是否询问方法如何返回整数或DALCountry类型？



这很容易。你不能。您必须更好地规划代码。方法只能返回单个类型。它不能返回多种类型。解决方案＃1是最好的解决方案，因为DALCountry类可以保存比单个整数更有意义的信息。

Your question doesn't make a lot of sense.

Are you asking how to overload a method with a copy that takes the same parameter type, a string in your case, and differs only by the return type? Are you asking how a method can return either an integer OR a DALCountry type?

It's easy. You can't. You must plan your code better. A method can only ever return a single type. It cannot return multiple types. Solution #1 is the best solution as a DALCountry class can hold much more meaningful information than a single integer can ever hold.

'CreateCountry不是声明为int。它返回一个'int，它需要一个'字符串参数。



'DALCountry类中的'CreateCountry方法必须与您在此处显示的'CreateCountry方法不同，或者：该方法会递归调用自身，直到出现堆栈溢出错误。



此处没有重载字符串变量。

'CreateCountry is not "declared as int." It returns an 'int, and it takes a 'string parameter.

The 'CreateCountry method in the 'DALCountry class must be different from the 'CreateCountry method you show here, or: the method would call itself recursively until there was a stack overflow error.

There is no "overloaded string variable" here.

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