Text format conversion (Text and Html)

Code

     public   string  writeStr( string  oldStr)
    {
         // oldStr=oldStr.Replace("''","'");   
        oldStr  =  oldStr.Replace( "     " ,  "   " );
        oldStr  =  oldStr.Replace( " &lt; " ,  " < " );
        oldStr  =  oldStr.Replace( " &gt; " ,  " > " );
        oldStr  =  oldStr.Replace( " <br/> " ,  " \n " );
        oldStr  =  oldStr.Replace( " &nbsp;&nbsp;&nbsp; " ,  " \t " );
        oldStr  =  oldStr.Replace( " &quot; " ,  " \ "" );
         return  oldStr;
    }
     public   string  readStr( string  oldStr)
    {
         // oldStr=oldStr.Replace("'","''");   
        oldStr  =  oldStr.Replace( " &nbsp; " ,  "     " );
        oldStr  =  oldStr.Replace( " < " ,  " &lt; " );
        oldStr  =  oldStr.Replace( " > " ,  " &gt; " );
        oldStr  =  oldStr.Replace( " \n " ,  " <br/> " );
        oldStr  =  oldStr.Replace( " \t " ,  " &nbsp;&nbsp;&nbsp; " );
        oldStr  =  oldStr.Replace( " \ "" ,  " & quot; " );
         return  oldStr;
    }

 At the time of filing the articles newline Convert.ToString ((char) 13) + Convert.ToString ((char) 10) replacing the HTML code </ P>, what is <BR>

Reproduced in: https: //www.cnblogs.com/qiangshu/archive/2010/05/07/1729422.html