Dictionary<string,string> list=new Dictionary<string,string>;

foreach(var item in list)
{
      Console.WriteLine(item.Key+item.Value);
}
//KeyValuePair<T,K>
foreach(KeyValuePair<string,string> kv in list)
{
      Console.WriteLine(kv.Key+kv.Value);
}
//通过键的集合取
foreach(string key in list.Keys)
{
      Console.WriteLine(key+list[key]);
}