ArrayList，Hashtable，List<T>，Dictionary<K,V>

Posted 2020-06-16

1.ArrayList  

            ArrayList list = new ArrayList();
//for遍历
            for (int i = 0; i < list.Count; i++)
            {
                SE se=(SE)list[i];
               Console.WriteLine(se.Name);
            }
//foreach遍历
          foreach(Object obj in list)
          {
              SE se=(SE)list[i];
              Console.WriteLine(se.Name);      
           }

2.Hashtable

Hashtable  list=new Hashtable();

//Hashtable不能用索引访问，所以遍历一个Hashtable只能用foreache()方法

//遍历Key
foreach(Object obj in list.Keys)
{
  Console.WriteLine((string)obj);
}
//遍历Value
foreach(Object obj in list.Values)
{
  SE se=(SE)obj;
  Console.WriteLine(se.Name);
}
//同时遍历，DictionaryEntry一个结构
foreach(DictionaryEntry en in list){
  Console.WriteLine(se.Keys);
  COnsole.WriteLine(((SE)en.Value).Name);
}

3.List<T>

          
//for遍历
            for (int i = 0; i < list.Count; i++)
            {
                //遍历时不需要类型转换
               Console.WriteLine(list[i]);
            }
//foreach遍历
          foreach(SE obj in list)
          {
                //遍历时不需要类型转换
              Console.WriteLine(obj);      
           }
//

4.Dictionary<K,V>

//遍历Values
foreach(SE se in list.Values)
{
     //遍历时不需要类型转换
     Console.WriteLine(se);
}

//同时遍历
foreach(KeyValuePair<string,SE> en in list)
{
  Console.WriteLine(en.Key);
  Console.WriteLine(en.Value.Name);
}
//KeyValuePair<TKey,TValue>是一个泛型结构