截取汉字超出 的部分...表示

///   <summary>    
   ///   将指定字符串按指定长度进行剪切，    
   ///   </summary>    
   ///   <param   name= "oldStr "> 需要截断的字符串 </param>    
   ///   <param   name= "maxLength "> 字符串的最大长度 </param>    
   ///   <param   name= "endWith "> 超过长度的后缀 </param>    
   ///   <returns> 如果超过长度，返回截断后的新字符串加上后缀，否则，返回原字符串 </returns>    
   public static string StringTruncat(string oldStr, int maxLength, string endWith)   
   {   
       if (string.IsNullOrEmpty(oldStr))   
           //   throw   new   NullReferenceException( "原字符串不能为空 ");    
           return oldStr + endWith;   
       if (maxLength < 1)   
           throw new Exception("返回的字符串长度必须大于[0] ");   
       if (oldStr.Length > maxLength)   
       {   
           string strTmp = oldStr.Substring(0, maxLength);   
           if (string.IsNullOrEmpty(endWith))   
               return strTmp;   
           else  
               return strTmp + endWith;   
       }   
       return oldStr;   
   }