从哈希表中找到一个值 [英] Find a value from a hashtable

问题描述

如果我有一个通用列表，我会做这样的事情

If I were having a Generic list I would have done some thing like this

myListOfObject.FindAll(x=>(x.IsRequired==false));

如果我需要在 Hashtable 中做类似的事情怎么办?复制到临时 hashtable 并进行循环和比较将是我最后尝试做的事情:-(

What if I need to do similar stuff in Hashtable? Copying to temporary hashtable and looping and comparing would be that last thing I would try :-(

推荐答案

首先，使用 System.Collections.Generic.Dictionary< TKey，TValue> 获得更好的强类型支持，而不是哈希表.

Firstly, use System.Collections.Generic.Dictionary<TKey, TValue> for better strong-type support as opposed to Hashtable.

如果您只需要查找一个键或一个值，请使用方法 ContainsKey(对象键)或 ContainsValue(对象值) Hashtable 类型.

If you need to just find one key or one value, use the methods ContainsKey(object key) or ContainsValue(object value), both of which are found on the Hashtable type.

或者您可以走得更远，并在 Hashtable 部分上使用linq扩展:

Or you can go further and use linq extensions on the Hashtable parts:

Hashtable t = new Hashtable();
t.Add("Key", "Adam");

// Get the key/value entries.
var itemEntry = t.OfType<DictionaryEntry>().Where(de => (de.Value as string) == "Adam");

// Get just the values.
var items = t.Values.OfType<string>().Where(s => s == "Adam");

// Get just the keys.
var itemKey = t.Keys.OfType<string>().Where(k => k == "Key");

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