Question

在我的代码中，我通过迭代foreach在DataRow内的值中添加了一个列表。我的代码如下，

ActivityUserResult Result = new ActivityUserResult();
Result.TransacDetails = new List<TransactionStatistics>();
foreach (DataRow row in ds.Tables[2].Rows)
{
    Result.TransacDetails.Add(new TransactionStatistics()
    {
        Id = Convert.ToString(row["Id"]),,
        AssistCount = Convert.ToInt32(row["AssistCount"]),
        WaitTime = Convert.ToInt32(row["WaitTime"]),
        AverageStandardWaitTime = (Convert.ToInt32(row["WaitTime"]) / Convert.ToInt32(row["AssistCount"])) / 60                    
    });
}

我需要通过将AverageStandardWaitTime除以WaitTime得到AssistCount的值。为此，我在循环中添加了此

AverageStandardWaitTime = (Convert.ToInt32(row["WaitTime"]) / Convert.ToInt32(row["AssistCount"])) / 60

但有时AssistCount的值将为零。所以我遇到了这个错误。

System.DivideByZeroException: 'Attempted to divide by zero.'

如何检查AssistCount的值是否为零？如果不为零，则需要除法，否则需要避免除法，需要将AverageStandardWaitTime的值设置为0

Answer 1

您可以为此使用三元运算符，这很简单：

AverageStandardWaitTime = (Convert.ToInt32(row["AssistCount"]) > 0 
                            ? Convert.ToInt32(row["WaitTime"]) / Convert.ToInt32(row["AssistCount"]) 
                            : 0)

如果愿意，可以重新使用转换后的值，而不是每次都转换该值。

foreach (DataRow row in ds.Tables[2].Rows)
{
    Result.TransacDetails.Add(new TransactionStatistics()
    {
        Id = Convert.ToString(row["Id"]),,
        AssistCount = Convert.ToInt32(row["AssistCount"]),
        WaitTime = Convert.ToInt32(row["WaitTime"]),
        AverageStandardWaitTime = (Convert.ToInt32(row["WaitTime"]) > 0 
                                   ? (Convert.ToInt32(row["WaitTime"]/Convert.ToInt32(row["AssistCount"]))/60 
                                   :  Convert.ToInt32(row["WaitTime"])
                                  )                   
    });
}

Answer 2

您可以创建函数，然后对其进行调用，这样您就可以获得清晰的代码和有关某些数据错误的正确消息

public double CalculateAverageStandardWaitTime(DataRow row)
{
  int waitTime = Convert.ToInt32(row["WaitTime"];
  int assistcount =  Convert.ToInt32(row["AssistCount"]);
  if(assistcount != 0 ) {
    return (Convert.ToInt32(row["WaitTime"]) / 
         Convert.ToInt32(row["AssistCount"])) / 60;
  }
  else {
   //log message that value is less then zeor 
   //return some defautl value 
   return -1; //0 
  }
}

您的代码将是

Result.TransacDetails.Add(new TransactionStatistics()
    {
        Id = Convert.ToString(row["Id"]),,
        AssistCount = Convert.ToInt32(row["AssistCount"]),
        WaitTime = Convert.ToInt32(row["WaitTime"]),
        AverageStandardWaitTime = CalculateAverageStandardWaitTime(row)                  
    });

如何在DataRow中检查值为零

2 个答案: