.net中使用正则表达式替换字符串

Dim patToDate As String = "(TO_DATE\(')(.+?)(','yyyy.+?'\))"
Dim patCDate As String = "(CDate\(')(.+?)('\))"
sqlStr = Regex.Replace(sqlStr, patToDate, "$2", RegexOptions.IgnoreCase)
sqlStr = Regex.Replace(sqlStr, patCDate, "$2", RegexOptions.IgnoreCase)

以上使用了组捕获和组替换