为什么ConcurrentDictionary.TryRemove需要第二个说法出来？ [英] Why does ConcurrentDictionary.TryRemove require a second out argument?

问题描述

我只希望可以删除该值。我不需要事后使用变量。为什么不包括在这里是不需要第二个参数的重载？

I only want to remove a value.. I don't need to use the variable afterwards. Why not include an overload where this second parameter was not required?

难道我真的只是存储在一个临时的局部变量，而不是使用它，并有垃圾收藏家收集它，当方法结束？似乎是相当愚蠢的。

Do I really have to just store it in a temporary local variable, not use it, and have the garbage collector collect it when the method ends? Seems rather silly..

功能： HTTP ：//msdn.microsoft.com/en-us/library/dd287129.aspx

推荐答案

您可以创建正是你想要的方式：

You can create exactly the method you want:

public static class ConcurrentDictionaryEx {
  public static bool TryRemove<TKey, TValue>(
    this ConcurrentDictionary<TKey, TValue> self, TKey key) {
    TValue ignored;
    return self.TryRemove(key, out ignored);
  }
}

更新：或者，作为 Dialecticus在评论中提到，只是使用的 删除 。但需要注意的是，因为它是一个显式接口实现，你需要参考的的IDictionary< TKEY的，TValue> ，从而导致你回到创建扩展方法，如果您要避免铸造 ConcurrentDictionary< TKEY的，TValue> 引用：

UPDATE: Or, as Dialecticus mentioned in the comments, just use Remove. But note that, since it's an explicit interface implementation, you'll need a reference to an IDictionary<TKey, TValue>, which leads you back to creating an extension method if you want to avoid casting a ConcurrentDictionary<TKey, TValue> reference:

public static class ConcurrentDictionaryEx {
  public static bool Remove<TKey, TValue>(
    this ConcurrentDictionary<TKey, TValue> self, TKey key) {
      return ((IDictionary<TKey, TValue>)self).Remove(key);
  }
}

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