正则表达式

1.string s="@张三 @李四 ";

获取“张三”和“李四”

MatchCollection mc = Regex.Matches(s, @"@(?<truename>S+)[ |　]");

for (int i = 0; i < mc.Count; i++) //在输入字符串中找到所有匹配
{
var trueName=mc[i].Groups["truename"].Value);

}

2.string s="张三：say something<br/>李四：say something<br/>

替换成"<a name='AtTrueName'>张三</a>：say something<br/><a name='AtTrueName'>李四</a>：say something<br/>

即：在姓名的前后插入内容

Regex.Replace(s, "(?<begin>^|>)(?<truename>[^：]*)：", "${begin}<a name='AtTrueName'>${truename}</a>：")