C# 正则表达式替换的问题,

Question

var formatString = "{a}xxxx{b}xxx{c}xxx{d}xxx{e}xxx";
Dictionary<string, string> dic = new Dictionary<string, string>
{
　　{ "a","xxxx" },
　　{ "b","xxx" },
　　{ "c","x" },
　　{ "e","xxxxxx" },
　　{ "d","xxxxxxx" },
};

如上:

　　如何使用dic中的值去替换formatString {\w+} 字符串呢

有木有大神知道, 请指点感激不尽