把一个vbs函数，改成c#

Question

用c#操作字符不太熟悉，请大家帮帮忙'**************************************************
'函数名：gotTopic
'作  用：截字符串，汉字一个算两个字符，英文算一个字符
'参  数：str   ----原字符串
'       strlen ----截取长度
'返回值：截取后的字符串
'**************************************************
function gotTopic(str,strlen)
if str="" then
gotTopic=""
exit function
end if
dim l,t,c, i
str=replace(replace(replace(replace(str,"&nbsp;"," "),"&quot;",chr(34)),"&gt;",">"),"&lt;","<")
l=len(str)
t=0
for i=1 to l
c=Abs(Asc(Mid(str,i,1)))
if c>255 then
t=t+2
else
t=t+1
end if
if t>=strlen then
gotTopic=left(str,i) & "…"
exit for
else
gotTopic=str
end if
next
gotTopic=replace(replace(replace(replace(gotTopic," ","&nbsp;"),chr(34),"&quot;"),">","&gt;"),"<","&lt;")
end function

Answer 1

好复杂,up我喜欢这样写:s = replace (s,"&nbsp;"," ")
s = replace (s,"&quot;",chr(34))

Answer 2

http://dotnet.aspx.cc/ShowDetail.aspx?id=48596EF2-8C16-47EE-1CD3-174E44FA9E24

Answer 3

没仔细检查:
        string gotTopic(string strSrc,int iLength)
        {
            if (strSrc==null||strSrc.Length==0) return null;            strSrc=strSrc.Replace("&nbsp;"," ");
            strSrc = strSrc.Replace("&quot;", Convert.ToString((char)34));
            strSrc=strSrc.Replace("&gt;",">");
            strSrc=strSrc.Replace("&lt;","<");            int iCurPos =0;
            int iCurLength=strSrc.Length;            for(int i=0;i<iCurLength;i++)
            {
                if (Math.Abs(char.Parse(strSrc.Substring(i,1)))>255)
                    iCurPos+=2;
                else
                    iCurPos+=1;                if (iCurPos>=iLength)
                {
                    strSrc=strSrc.Substring(0,i) +"…";
                    break;
                }
            }            strSrc = strSrc.Replace(" ", "&nbsp");
            strSrc = strSrc.Replace(Convert.ToString((char)34), "&quot;");
            strSrc = strSrc.Replace(">", "&gt;");
            strSrc = strSrc.Replace("<", "&lt;");
            return strSrc;
        }