试试
string re = "<%#(?<item>.*?)%>";
string source = "价格:<%# price %> 元。数量:<%# Count %>个。类别:<%# Type %>";
foreach (System.Text.RegularExpressions.Match item in System.Text.RegularExpressions.Regex.Matches(source, re))
{
Response.Write(item.Value + "<br />");
}