c# - 从 try{} catch{} 访问变量

Question

我试图在 try{} catch{} 方法之后访问变量(特别是 ArrayList)。

try 
{
//Here I would import data from an ArrayList if it was already created.
}
catch
{  
//Create new array list if it couldn't find one.
ArrayList items = new ArrayList();
}

无论如何，ArrayList 项目将被创建，我希望能够访问它。我之前尝试初始化 ArrayList，如下所示:

ArrayList items;
try 
{
//Here I would import data from an ArrayList if it was already created.
}
catch
{  
//Create new array list if it couldn't find one.
ArrayList items = new ArrayList();
}

但是我无法在 try{} catch{} block 中做任何事情，因为它说“它已经被创建了”。

我希望能够创建一个程序来记住它之前运行时的操作，但我似乎无法围绕正确的概念取得进展。

Answer 1

您必须将范围向外移动:

ArrayList items;    // do not initialize
try 
{
   //Here I would import data from an ArrayList if it was already created.
   items = ...;
}
catch
{  
  //Create new array list if it couldn't find one.
  items = new ArrayList();  // note no re-declaration, just an assignment
}

但让我给你一些提示:

• 不要在ArrayList()上投入太多，看List<T>相反。
• 请谨慎使用 catch {} .
  出了点(非常)错误，提供默认答案通常不是正确的策略。