C# Dictionary学习

http://www.cnblogs.com/gdjlc/archive/2010/01/22/2086922.html

http://wenku.baidu.com/link?url=TOgeedl02Q3VAQ4DNqRtlJ8W67d5d6yGk3sY1YDOPgPLpu0E5CknLp2Rf0fuAmIuoR5swSWxiz74PtpAda4nWeZaci1xiTmIEsrQFzBlYZi

用Linq的方式去查询

http://www.cnblogs.com/mingmingruyuedlut/archive/2013/05/23/3067227.html

1：最直白的循环遍历方法，可以分为遍历key--value键值对以及所有的key两种表现形式

2：用Linq的方式去查询（当然了这里要添加对应的命名空间 using System.Linq）

如下为一个十分简单的代码示例：

private void GetDicKeyByValue()
        {
            Dictionary<string, string> dic = new Dictionary<string, string>();
            dic.Add("", "");
            dic.Add("", "");
            dic.Add("", "");
            //foreach KeyValuePair traversing
            foreach (KeyValuePair<string, string> kvp in dic)
            {
                if (kvp.Value.Equals(""))
                {
                    //...... kvp.Key;
                }
            }

            //foreach dic.Keys
            foreach (string key in dic.Keys)
            {
                if (dic[key].Equals(""))
                {
                    //...... key
                }
            }

            //Linq
            var keys = dic.Where(q => q.Value == "").Select(q => q.Key);  //get all keys

            List<string> keyList = (from q in dic
                                    where q.Value == ""
                                    select q.Key).ToList<string>(); //get all keys

            var firstKey = dic.FirstOrDefault(q => q.Value == "").Key;  //get first key
        }