替換固定字符沒必要用正則表達式，效率差。
stringstr="line1\r\nline2\nline3\r";
str=str.Replace(System.Environment.NewLine,"");//OK
str=str.Replace("\r","").Replace("\n","");//也OK
                            

stringpattern=@"\r*\n";
Regexrgx=newRegex(pattern);
stringoutputStr=rgx.Replace(strpageContent,"");