Vb.net 如何对持续时间求和并在报告中显示

我得到的错误是Sum未声明或不在当前范围内。我需要在我的报告页脚中显示按employeeId分组的总小时数

关于这件事有什么建议吗？我可能会错在哪里。

---

提前感谢

好的，VB.Net不是我的常规c语言，因此如果有任何错误，请原谅我

首先，您似乎有一个奇怪的查询语法和流畅语法的混合体，需要小心处理。此外，我认为无需计算

有许多EmployeeViewModel，每个都有单独的工作时间，但也有一个从其他ViewModel组成的总数，这也是没有意义的。你将如何展示？稍后应为报告计算总计，或者您需要更改ViewModel以获得工作小时列表和总计。此外，您不应该在此处设置HoursWorked，它应该是一个只读属性，返回计算值

我给你的第一个建议是。如果没有分组或使用聚合，Sum不可用

因此，我的解决方案如下：

Public Function TotalHoursWorked() As IEnumerable(Of Reporting.EmployeeViewModel) Implements IReportRepository.TotalHoursWorked**

    Dim qryEmployee = From emp In db.Employee _
    .Select(Function(emp) New With {emp.EmployeeId, emp.EmployeeName}).AsEnumerable

    Dim qryHoursWorked = From hw In db.HoursWorked
                             Select New With {hw.EmployeeId, hw.HoursWorkedStart, hw.HoursWorkedEnd}

    Return (From emp In qryEmployee _
            Join hw In qryHoursWorked On emp.EmployeeId Equals hw.EmployeeId _
            Select New Reporting.EmployeeViewModel With {
                 .EmployeeName = emp.EmployeeName,
                 .HoursWorkedStart = RoundClockInTime(hw.HoursWorkedStart),
                 .HoursWorkedEnd = If(hw.HoursWorkedEnd.HasValue, RoundClockOutTime(hw.HoursWorkedEnd), hw.HoursWorkedEnd),
                 .HoursWorked = (.HoursWorkedStart - .HoursWorkedEnd),
                 .TotalHours = Sum(.HoursWorked)
             })

End Function

现在，如果您按照上面的步骤创建一个新类，例如带有属性Start、End的WorkingHours，以及返回Start-End的只读属性HoursWorked

然后，您可以在EmployeeViewModel上拥有一个Total属性，如果您想将工作小时数求和，该属性将使用LINQ来给出总计

更像：

Dim Employees = From Employee In db.Employee
                Select New With 
                {
                    .EmployeeId = Employee.EmployeeId,
                    .Name = Employee.EmployeeName
                }

Dim WorkingHours = From HoursWorked In db.HoursWorked
                  Select New With 
                  {
                      .EmployeeId = HoursWorked.EmployeeId,
                      .Start = HoursWorked.HoursWorkedStart
                      .End = HoursWorked.HoursWorkedEnd
                  }

Dim EmployeeWorkingHours = From Employee In Employees
                          Group Join HoursWorked In WorkingHours
                          On Employee.EmployeeId Equals HoursWorked.EmployeeId
                          Into EmployeeHoursWorked = Group, _
                              TotalHours = Sum(HoursWorked.Start - HoursWorked.End)
                          From EmployeeHours in EmployeeHoursWorked
                          Select New Reporting.EmployeeViewModel With
                          {
                              .EmployeeName = Employee.Name
                              .HoursWorkedStart = EmployeeHours.Start
                              .HoursWorkedEnd = EmployeeHours.End
                              .HoursWorked = (EmployeeHours.Start - EmployeeHours.End)
                              .TotalHours = CType(TotalHours, Integer?) _
                                  .GetValueOrDefault(0)
                          }

---

我想我可以帮你，但为了方便起见，你能告诉我db.Employee和db.HoursWorked的具体组成吗？您选择匿名类型是因为您不需要/不需要所有其他属性吗？我死得和您的代码完全一样，但仍然收到错误：重载解析失败，因为无法使用这些参数调用可访问的总和：我的代码与您的代码完全一样，仍然收到错误：重载解析失败，因为没有可以使用以下参数调用可访问总和：扩展方法的公共函数Sumselector As System.FuncOf，Decimal？在“System.Linq.Enumerable”中定义为“Decimal”：无法将类型为“System.TimeSpan”的值转换为“Decimal”。由于空间问题，我删除了Long、string、Double、DateTime等类型的其他字段。第一个字段我认为您需要使用您尝试过的新代码更新您的问题，然后我才能提供帮助。另一个很简单你想转换时间跨度？到小数点？这是无效的。把你试过的贴出来，我会帮你的。

Dim WorkingHours = From HoursWorked In db.HoursWorked
                  Select New WorkingHours With 
                  {
                      .EmployeeId = HoursWorked.EmployeeId,
                      .Start = HoursWorked.HoursWorkedStart
                      .End = HoursWorked.HoursWorkedEnd
                  }

Dim EmployeeWorkingHours = From Employee In Employees
                          Group Join HoursWorked In WorkingHours
                          On Employee.EmployeeId Equals HoursWorked.EmployeeId
                          Into EmployeeHoursWorked = Group
                          Select New Reporting.EmployeeViewModel With
                          {
                              .EmployeeName = Employee.Name
                              ' This is an Enumerable<WorkingHours>
                              ' which you can use in the ViewModel
                              ' to calculate the total.
                              .WorkingHours = EmployeeHoursWorked
                          }