KeyValuePair VS的DictionaryEntry

问题描述

这是通用版本的DictionaryEntry KeyValuePair之间的区别是什么？

What is the difference between KeyValuePair which is the generic version and DictionaryEntry?

为什么KeyValuePair来代替的DictionaryEntry的泛型类Dictionary？

Why KeyValuePair is used instead of DictionaryEntry in generic Dictionary class?

推荐答案

KeyValuePair< TKEY的，TValue> 代替使用的DictionaryEntry ，因为它是泛型。使用 KeyValuePair 1所述的优势; TKEY的，TValue> 的是，我们可以给编译器有什么是我们的字典详细信息。为了扩大克里斯的例子（在此我们有一个包含两个字典<字符串，整数> 对）。

KeyValuePair<TKey,TValue> is used in place of DictionaryEntry because it is generified. The advantage of using a KeyValuePair<TKey,TValue> is that we can give the compiler more information about what is in our dictionary. To expand on Chris' example (in which we have two dictionaries containing <string, int> pairs).

Dictionary<string, int> dict = new Dictionary<string, int>();
foreach (KeyValuePair<string, int> item in dict) {
  int i = item.Value;
}

Hashtable hashtable = new Hashtable();
foreach (DictionaryEntry item in hashtable) {
  // Cast required because compiler doesn't know it's a <string, int> pair.
  int i = (int) item.Value;
}

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