比如下面的代码 如何用.net获取字符串里所有tid= 的值的集合啊?<a href="read.php?tid=121247" id="">jsghbdljgh</a>1234214325
<a href="read.php?tid=321257" id="">gojkgkjngijgihj</a>3sdfdg
<a href="read.php?tid=134523" id="">fdhfghtrwrwer</a>dfgdfg
<a href="read.php?tid=131227" id="">jsghbdljgh</a>123345
<a href="read.php?tid=351257" id="">gojkgkjngijgihj</a>3sdfdg
<a href="read.php?tid=164523" id="">fdhfghtrwrwer</a>dfgdfg