c#hashtable，Dictionary泛型注意！

hashtable 会将所有的类型全部转为对象，所以能存各种类型，换句话说item的类型可能不同，这样的话可能会造成风险，Dictionary因为有泛型限制，所以编译器会校验item的类型，如果类型不同编译阶段会报错，

using System; using System.Collections; using System.Collections.Generic; using System.Linq; using System.Text; namespace hashtable和Dictionary的泛型实验 { class Program { static void Main(string[] args) { Hashtable ht = new Hashtable(); ht.Add(1,1); ht.Add("1","1"); foreach (var item in ht.Keys) { Console.WriteLine("Key = {0},Value = {1}", item,ht[item]); } System.Threading.Thread.Sleep(2000); Console.WriteLine("------------------------------"); Dictionary<String, String> d = new Dictionary<string, string>(); d.Add("a","1"); d.Add("A","1"); foreach (var item in d.Keys) { Console.WriteLine("Key = {0},Value = {1}", item, d[item]); } System.Threading.Thread.Sleep(2000); } } }