我需要使用多个using语句吗? [英] Do I need to use multiple using statements?

问题描述

出于实用性考虑，这两个课程都是一次性的.

我了解using块的作用.但是我不确定它可以使用或需要使用的所有方式.

I understand what a using block does. But I'm not sure of all of the ways it can or needs to be used.

例如，这是正确的吗?

using (MyClass myClass = new MyClass(params))
{
     myClass.name = "Steve";

     SecondClass myClassSecond = new SecondClass(params);
     myClassSecond.name = "George";
     myClassSecond.msg = "Hello Man in the Yellow Hat";
}

以上两个类别都被处理掉了吗?

Are both classes above disposed of?

还是在using语句中都需要两个?

Or do I need both inside a using statement?

using (MyClass myClass = new MyClass(params))
{
     myClass.name = "Steve";

     using (SecondClass myClassSecond = new SecondClass(params))
     {
          myClassSecond.name = "George";
          myClassSecond.msg = "Hello Man in the Yellow Hat";
     }
}

以上是否正确，还是有更好的方法来使用多个using语句?

Is the above correct, or is there a better way to use multiple using statements?

推荐答案

• 使用 using 语句，程序员可以指定使用资源的对象何时释放它们.
• 提供给using语句的对象必须实现 IDisposable 接口.
• 此接口提供了 Dispose 方法，该方法应释放对象的资源.
• The using statement allows the programmer to specify when objects that use resources should release them.
• The object provided to the using statement must implement the IDisposable interface.
• This interface provides the Dispose method, which should release the object's resources.

以下是显示using语句使用的示例:

Here is the sample showing use of using statement:

using System;
//Object of this class will be given to using hence IDisposable
class C : IDisposable        
{
    public void UseLimitedResource()
    {
        Console.WriteLine("Using limited resource...");
    }

    //Dispose() Method
    void IDisposable.Dispose()
    {
        Console.WriteLine("Disposing limited resource.");
    }
}

class Program
{
    static void Main()
    {
        using (C c = new C())  //Object of Class defined above
        {
            c.UseLimitedResource();
            //Object automatically disposed before closing.
        }                            
        Console.WriteLine("Now outside using statement.");
        Console.ReadLine();
    }
}

在以下情况下可以退出using语句:

A using statement can be exited either when:

• 达到 using 语句的末尾或
• 如果引发异常并且控制权在语句结束之前离开语句块.

哪种方法合适?

正如你所说的

出于实用性考虑，这两类都是一次性的

Both classes for practicality sake are disposable

.，那么您的第二种方法就是合适的方法.即:

., then your second approach is the appropriate one. that is:

using (MyClass myClass = new MyClass(params))
{
     myClass.name = "Steve";

     using (SecondClass myClassSecond = new SecondClass(params))
     {
          myClassSecond.name = "George";
          myClassSecond.msg = "Hello Man in the Yellow Hat";
     }
}

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