用户代码未处理格式异常

@foreach (var result in Model)
      {              
        ////var num=Convert.ToInt32(x);
        //int n=int.Parse(x);
        //int n=Integer.parseInt(x);            
      if (Convert.ToInt64(@result.Difference) < 0)
      {
      <tr>
        <td>@result.SalesIncentiveBuckets
        </td>
        <td>@result.CurrentMonth
        </td>
        <td>@result.SameMonthPrevYear
        </td>
        <td style="color:Red;">@result.Difference
        </td> 
        <td>@result.BonusAmount
        </td>
      </tr>
      }
      else
      {
      <tr>
         <td>@result.SalesIncentiveBuckets
         </td>
         <td>@result.CurrentMonth
         </td>
         <td>@result.SameMonthPrevYear
         </td>
         <td>@result.Difference
         </td> 
         <td>@result.BonusAmount
         </td>
       </tr>
      }
    }

在我的模型中，差异是一个字符串，我想将其转换为整数我尽我所能尝试了，但它显示此错误：

输入字符串格式不正确