我正在开发一个跟踪加油的应用程序。每条记录都存储有关加油站访问的数据。我决定在数据库中存储尽可能少的信息并在控制器中进行计算。
这是我的模型：
public class Refuel
{
#region Properties
public int id { get; set; }
public int mileage { get; set; }
public DateTime date { get; set; }
public Nullable<double> volume { get; set; }
public Nullable<double> price { get; set; }
public Nullable<int> imageId { get; set; }
public Nullable<int> gasstationId { get; set; }
public virtual Gasstation Gasstation { get; set; }
public virtual Image Image { get; set; }
#endregion
#region Methods
public int distance { get; set; }
[DisplayFormat(DataFormatString = "€ {0:0.00}")]
public Nullable<double> totalPrice
{
get
{
return volume * price;
}
}
[DisplayFormat(DataFormatString = "{0:0.00}")]
public Nullable<double> consumption
{
get
{
if (distance > 0)
return volume / distance * 100;
else
return 0;
}
}
[DisplayFormat(DataFormatString = "{0:0}")]
public Nullable<double> consumption2
{
get
{
if (distance > 0)
return distance / volume;
else
return 0;
}
}
[DisplayFormat(DataFormatString = "{0:0.00}")]
public Nullable<double> mileageLeft
{
get
{
return volumeLeft * consumption2;
}
}
[DisplayFormat(DataFormatString = "{0:0.00}")]
public Nullable<double> volumeLeft
{
get
{
double? d = 45 - volume;
return d;
}
}
#endregion
}
如您所见，我对这里的距离没有做任何事情。我在一个特定记录的详细信息页面中计算距离。
我现在要做的是在索引页面上做一个总结，总结距离并计算平均消耗。这都是相对于距离的，但此时这是一个空场。
在索引页面上显示所有记录的列表时，我遇到了同样的问题。距离和消耗列是空的。
在那一点上填充距离的最佳方法是什么？还是将距离存储在数据库中会更好吗？
这是我的索引函数：
[HttpGet]
[Authorize]
public ActionResult Index(string sortOrder, int? page)
{
ViewBag.CurrentSort = sortOrder;
ViewBag.NameSortParm = String.IsNullOrEmpty(sortOrder) ? "asc" : "";
List<Refuel> rf = db.Refuels.ToList();
var refuels = from t in db.Refuels select t;
switch (sortOrder)
{
case "asc":
refuels = refuels.OrderBy(q => q.mileage);
break;
default:
refuels = refuels.OrderByDescending(q => q.mileage);
break;
}
// statistieken
ViewBag.count = rf.Count();
ViewBag.distance = rf.Sum(q => q.distance);
ViewBag.volume = rf.Sum(q => q.volume);
ViewBag.consumption = String.Format("{0:0.0}", rf.Where(q => q.consumption > 0).Average(q => q.consumption));
ViewBag.consumption2 = String.Format("{0:0.0}", rf.Where(q => q.consumption2 > 0).Average(q => q.consumption2));
ViewBag.cost = String.Format("{0:c2}", rf.Sum(q => q.totalPrice));
int pageSize = 10;
int pageNumber = (page ?? 1);
return View(refuels.ToPagedList(pageNumber, pageSize));
}
编辑： 设法修复摘要部分，当然我可以使用最后和第一英里来获得总行驶距离：
ViewBag.count = tb.Count();
ViewBag.distance = tb.Last().mileage - tb.First().mileage;
ViewBag.volume = tb.Sum(q => q.volume);
ViewBag.consumption = String.Format("{0:0.0}", ViewBag.volume / ViewBag.distance * 100);
ViewBag.consumption2 = String.Format("{0:0.0}", ViewBag.distance / ViewBag.volume);
ViewBag.cost = String.Format("{0:c2}", tb.Sum(q => q.totalPrice));
我现在需要做的就是在索引表中显示每条记录的距离。这是我的 index.cshtml 中的循环：
@foreach (var item in Model)
{
<tr>
<td>
@Html.ActionLink(Html.DisplayFor(modelItem => item.mileage).ToString(), "Details", new { id = item.id })
</td>
<td>
@Html.DisplayFor(modelItem => item.date)
</td>
<td>
@Html.DisplayFor(modelItem => item.distance)
</td>
<td>
@Html.DisplayFor(modelItem => item.volume)
</td>
<td>
@Html.DisplayFor(modelItem => item.consumption)
</td>
<td>
@Html.DisplayFor(modelItem => item.totalPrice)
</td>
<td>
@Html.DisplayFor(modelItem => item.Gasstation.fullname)
</td>
</tr>
}