問題描述

我經常在 C++ 中使用的東西是讓一個類 A 通過 A 處理另一個類 B 的狀態進入和退出條件> 構造函數和析構函數，以確保如果該范圍內的某些內容引發異常，則 B 在退出范圍時將具有已知狀態.就首字母縮略詞而言，這并不是純粹的 RAII，但它仍然是一種既定模式.

Something I often used back in C++ was letting a class A handle a state entry and exit condition for another class B, via the A constructor and destructor, to make sure that if something in that scope threw an exception, then B would have a known state when the scope was exited. This isn't pure RAII as far as the acronym goes, but it's an established pattern nevertheless.

在C#中，我經常想做的事

In C#, I often want to do

class FrobbleManager
{
    ...

    private void FiddleTheFrobble()
    {
        this.Frobble.Unlock();
        Foo();                  // Can throw
        this.Frobble.Fiddle();  // Can throw
        Bar();                  // Can throw
        this.Frobble.Lock();
    }
}

需要這樣做

private void FiddleTheFrobble()
{
    this.Frobble.Unlock();

    try
    {            
        Foo();                  // Can throw
        this.Frobble.Fiddle();  // Can throw
        Bar();                  // Can throw
    }
    finally
    {
        this.Frobble.Lock();
    }
}

如果我想保證 FiddleTheFrobble 返回時的 Frobble 狀態.代碼會更好

if I want to guarantee the Frobble state when FiddleTheFrobble returns. The code would be nicer with

private void FiddleTheFrobble()
{
    using (var janitor = new FrobbleJanitor(this.Frobble))
    {            
        Foo();                  // Can throw
        this.Frobble.Fiddle();  // Can throw
        Bar();                  // Can throw
    }
}

FrobbleJanitor看起來大致像

class FrobbleJanitor : IDisposable
{
    private Frobble frobble;

    public FrobbleJanitor(Frobble frobble)
    {
        this.frobble = frobble;
        this.frobble.Unlock();
    }

    public void Dispose()
    {
        this.frobble.Lock();
    }
}

這就是我想要做的.現在現實趕上了，因為我 想要 使用 需要 FrobbleJanitor 使用 with using.我可以認為這是一個代碼審查問題，但有些事情困擾著我.