字符串清理

//字符串清理
  public  string InputText(string inputString, int maxLength)
  {   
   StringBuilder retVal = new StringBuilder();

   // 檢查是否爲空
   if ((inputString != null) && (inputString != String.Empty))
   {
    inputString = inputString.Trim();
    
    //檢查長度
    if (inputString.Length > maxLength)
     inputString = inputString.Substring(0, maxLength);
    
    //替換危險字符
    for (int i = 0; i < inputString.Length; i++)
    {
     switch (inputString[i])
     {
      case '"':
       retVal.Append("&quot;");
       break;
      case '<':
       retVal.Append("&lt;");
       break;
      case '>':
       retVal.Append("&gt;");
       break;
                        case '%':
                            retVal.Append("[%]");
                            break;
      default:
       retVal.Append(inputString[i]);
       break;
     }
    }    
    retVal.Replace("'", " ");// 替換單引號
   }
   return retVal.ToString();
   
  }