如何捕捉使用块与.NET 2.0中的异常？ [英] How to Catch an exception in a using block with .NET 2.0?

问题描述

我想利用using块越来越多的这些日子，我有一个对象实现IDisposable但有一件事我还没有想出是如何捕获异常，因为我会在一个正常的try / catch /终于...任何code样品给我指出了正确的方向？

I'm trying to leverage the using block more and more these days when I have an object that implements IDisposable but one thing I have not figured out is how to catch an exception as I would in a normal try/catch/finally ... any code samples to point me in the right direction?

编辑：此问题已通过回复看完之后修改。这是如何在使用块抛出一个异常，.NET 2.0？但实际上，我是在寻找一种方式来捕获这些异常的使用块内。

The question was modified after reading through the replies. It was "How to Throw an exception in a using block with .NET 2.0?" but I was actually looking for a way to catch these exceptions inside a using block.

我在寻找更详细的滚动使用块在我自己的追赶块。

I'm looking for more detail on rolling my own catching block inside a using block.

编辑：我想避免的是不必使用一个try / catch /终于我用块内像@Blair显示。但也许这是一个非问题...

What I wanted to avoid is having to use a try/catch/finally inside my using block like @Blair showed. But maybe this is a non issue...

编辑：@Blair，这正是我一直在寻找，感谢您的详细答复

@Blair, this is exactly what I was looking for, thanks for the detailed reply!

推荐答案

我真的不明白的问题 - 你抛出一个异常，你通常会。 如果 MyThing 工具的IDisposable ，那么：

I don't really understand the question - you throw an exception as you normally would. If MyThing implements IDisposable, then:

using ( MyThing thing = new MyThing() )
{
    ...
    throw new ApplicationException("oops");
}

和 thing.Dispose 你离开该块将被调用，因为异常的抛出。如果你想一个try / catch /终于结合和使用，您可以嵌套它们：

And thing.Dispose will be called as you leave the block, as the exception's thrown. If you want to combine a try/catch/finally and a using, you can either nest them:

try
{
    ...
    using ( MyThing thing = new MyThing() )
    {
        ...
    }
    ...
}
catch ( Exception e )
{
    ....
}
finally
{
    ....
}

（或者放的try / catch /终于在使用）：

(Or put the try/catch/finally in the using):

using ( MyThing thing = new MyThing() )
{
    ...
    try
    {
        ...
    }
    catch ( Exception e )
    {
        ....
    }
    finally
    {
        ....
    }    
    ...
} // thing.Dispose is called now

或者你也可以展开的使用和显式调用处置在最后块@ 吵闹证实，并称需要在终于任何额外的异常处理或-recovery code （或抓）。

Or you can unroll the using and explicitly call Dispose in the finally block as @Quarrelsome demonstrated, adding any extra exception-handling or -recovery code that you need in the finally (or in the catch).

编辑：在回答@ Toran比卢普斯，如果​​你需要从确保预留处理异常，你的处置方法被调用时，你要么必须使用使用和的try / catch /终于或展开的使用 - 我不认为有来完成你想要的任何其他方式

In response to @Toran Billups, if you need to process exceptions aside from ensuring that your Dispose method is called, you'll either have to use a using and try/catch/finally or unroll the using - I don't thinks there's any other way to accomplish what you want.

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