Vb.net 将参数从视图传递到实体框架OrderBy查询

我想知道如何从视图执行升序和降序查询。我目前的看法如下：

我理解我可以使用以下命令来订购视图：

Dim retrieveOrders = context.PBBuilds.Where(Function(x) x.User = userLoggedIn.Id).OrderBy(Function(x) x.Id).ToList()

我想通过一个动作链接将列标题和升序或降序传递给方法？（上下箭头位于每个标题附近）

OrderBy（）不接受字符串。。。。有人能帮忙吗？多谢各位

控制器：

   ' GET: Dashboard
    <Authorize(Roles:="Admin, Employee, User")>
    Function Index() As ActionResult

        Dim context = New ApplicationDbContext()
        Dim UserManager = New UserManager(Of ApplicationUser)(New UserStore(Of ApplicationUser)(context))
        Dim userLoggedIn = UserManager.FindById(User.Identity.GetUserId())
        Dim retrieveOrders = context.PBBuilds.Where(Function(x) x.User = userLoggedIn.Id).OrderBy(Function(x) x.Id).ToList()

        Dim BuildsVM = retrieveOrders.[Select](Function(build) New DashboardBuilds() With {
        .BuildNumber = build.Id,
        .DateCreated = build.TimeAndDate,
        .MyRef = build.CustRef,
        .NetCost = build.TotalNet
        }).ToList()

        Dim today = DateTime.Today.Date
        Dim tomorrow = DateTime.Today.Date.AddDays(1)
        Dim todaysBuild = retrieveOrders.Where(Function(build) build.TimeAndDate >= today And build.TimeAndDate <= tomorrow).ToList().Count()
        Dim monthlyBuild = retrieveOrders.Where(Function(build) build.TimeAndDate.Year = today.Year And build.TimeAndDate.Month = today.Month).ToList().Count()
        Dim yearlyBuild = retrieveOrders.Where(Function(build) build.TimeAndDate.Year = today.Year).ToList().Count()

        Dim total As Decimal = BuildsVM.Sum(Function(item) item.NetCost)
        Dim count As Integer = retrieveOrders.Count
        Dim Average As Decimal = 0.00

        If count > 0 Then
            Average = total / count
        End If


        Dim model = New GroupedDashBoardBuilds() With {
        .BuildInfos = BuildsVM,
        .TotalNet = Math.Round(total, 2),
        .AverageNet = Math.Round(Average, 2),
        .TotalUserBuild = count,
        .TotalUserBuildToday = todaysBuild,
        .TotalUserBuildMonth = monthlyBuild,
        .TotalUserBuildYear = yearlyBuild
        }

        Return View(model)
    End Function

Function Index(strColumnName As String, bolAscending As Boolean) As ActionResult

获取：仪表板 函数Index（）作为ActionResult Dim context=新的ApplicationDbContext（） Dim UserManager=newusermanager（属于ApplicationUser）（newuserstore（属于ApplicationUser）（上下文）） Dim userLoggedIn=UserManager.FindById（User.Identity.GetUserId（）） Dim retrieveOrders=context.PBBuilds.Where（函数（x）x.User=userLoggedIn.Id）.OrderBy（函数（x）x.Id）.ToList（） Dim BuildsVM=retrieveOrders。[选择]（函数（构建）新仪表板构建（）与{ .BuildNumber=build.Id， .DateCreated=build.TimeAndDate， .MyRef=build.CustRef， .NetCost=build.TotalNet })托利斯先生（） Dim today=DateTime.today.Date Dim明天=DateTime.Today.Date.AddDays（1） Dim todaysBuild=retrieveOrders.Where（函数（build）build.TimeAndDate>=今天和build.TimeAndDate 0然后 平均数=总数/计数 如果结束 Dim模型=新的GroupedDashBoardBuilds（），带有{ .BuildInfos=BuildsVM， .TotalNet=数学四舍五入（总计2）， .AverageNet=数学四舍五入（平均，2）， .TotalUserBuild=count， .TotalUserBuildToday=todaysBuild， .TotalUserBuildMonth=monthlyBuild， .TotalUserBuildYear=yearlyBuild } 返回视图（模型） 端函数

---

因为您要将字段名以及它是否要升序或降序传递到控制器中：

   ' GET: Dashboard
    <Authorize(Roles:="Admin, Employee, User")>
    Function Index() As ActionResult

        Dim context = New ApplicationDbContext()
        Dim UserManager = New UserManager(Of ApplicationUser)(New UserStore(Of ApplicationUser)(context))
        Dim userLoggedIn = UserManager.FindById(User.Identity.GetUserId())
        Dim retrieveOrders = context.PBBuilds.Where(Function(x) x.User = userLoggedIn.Id).OrderBy(Function(x) x.Id).ToList()

        Dim BuildsVM = retrieveOrders.[Select](Function(build) New DashboardBuilds() With {
        .BuildNumber = build.Id,
        .DateCreated = build.TimeAndDate,
        .MyRef = build.CustRef,
        .NetCost = build.TotalNet
        }).ToList()

        Dim today = DateTime.Today.Date
        Dim tomorrow = DateTime.Today.Date.AddDays(1)
        Dim todaysBuild = retrieveOrders.Where(Function(build) build.TimeAndDate >= today And build.TimeAndDate <= tomorrow).ToList().Count()
        Dim monthlyBuild = retrieveOrders.Where(Function(build) build.TimeAndDate.Year = today.Year And build.TimeAndDate.Month = today.Month).ToList().Count()
        Dim yearlyBuild = retrieveOrders.Where(Function(build) build.TimeAndDate.Year = today.Year).ToList().Count()

        Dim total As Decimal = BuildsVM.Sum(Function(item) item.NetCost)
        Dim count As Integer = retrieveOrders.Count
        Dim Average As Decimal = 0.00

        If count > 0 Then
            Average = total / count
        End If


        Dim model = New GroupedDashBoardBuilds() With {
        .BuildInfos = BuildsVM,
        .TotalNet = Math.Round(total, 2),
        .AverageNet = Math.Round(Average, 2),
        .TotalUserBuild = count,
        .TotalUserBuildToday = todaysBuild,
        .TotalUserBuildMonth = monthlyBuild,
        .TotalUserBuildYear = yearlyBuild
        }

        Return View(model)
    End Function

Function Index(strColumnName As String, bolAscending As Boolean) As ActionResult

您可以在如下选择的情况下实现逻辑：

Dim retrieveOrders As List(Of PBBuilds) = Nothing

Select Case strColumnName
    Case "Build"
        If bolAscending Then
            retrieveOrders = context.PBBuilds.Where(Function(x) x.User = userLoggedIn.Id).OrderBy(Function(x) x.Id).ToList()
        Else
            retrieveOrders = context.PBBuilds.Where(Function(x) x.User = userLoggedIn.Id).OrderByDescending(Function(x) x.Id).ToList()
        End If
    Case "My Reference"
        If bolAscending Then
            retrieveOrders = context.PBBuilds.Where(Function(x) x.User = userLoggedIn.Id).OrderBy(Function(x) x.FieldRelatedToMyReference).ToList()
        Else
            retrieveOrders = context.PBBuilds.Where(Function(x) x.User = userLoggedIn.Id).OrderByDescending(Function(x) x.FieldRelatedToMyReference).ToList()
        End If

    'Implement for Other Cases
End Select

Dictionary<string, Func<User, object>> ColumnAccessorMap = new Dictionary<string, Func<User, object>>()
{
    { "Build", user => user.ID },
    { "My Reference", user => user.MyReferenceProperty }
}

// etc...

context.MyTable.ToList().OrderBy(ColumnAccessorMap[strColumnName]);

---

如果您不关心数据库上运行的

OrderBy

，可以执行以下操作：

Dim retrieveOrders As List(Of PBBuilds) = Nothing

Select Case strColumnName
    Case "Build"
        If bolAscending Then
            retrieveOrders = context.PBBuilds.Where(Function(x) x.User = userLoggedIn.Id).OrderBy(Function(x) x.Id).ToList()
        Else
            retrieveOrders = context.PBBuilds.Where(Function(x) x.User = userLoggedIn.Id).OrderByDescending(Function(x) x.Id).ToList()
        End If
    Case "My Reference"
        If bolAscending Then
            retrieveOrders = context.PBBuilds.Where(Function(x) x.User = userLoggedIn.Id).OrderBy(Function(x) x.FieldRelatedToMyReference).ToList()
        Else
            retrieveOrders = context.PBBuilds.Where(Function(x) x.User = userLoggedIn.Id).OrderByDescending(Function(x) x.FieldRelatedToMyReference).ToList()
        End If

    'Implement for Other Cases
End Select

Dictionary<string, Func<User, object>> ColumnAccessorMap = new Dictionary<string, Func<User, object>>()
{
    { "Build", user => user.ID },
    { "My Reference", user => user.MyReferenceProperty }
}

// etc...

context.MyTable.ToList().OrderBy(ColumnAccessorMap[strColumnName]);

---

本质上，将列映射到访问器函数，该函数告诉排序时使用的

OrderBy

属性。同样，如果没有前面的

.ToList

调用，这将无法工作，这意味着排序是在本地进行的，而不是在SQL中进行的。

您始终可以执行查询，然后排序，我的意思是，首先获取数据，然后切换案例顺序？抱歉，这是另一个问题中的C#谢谢，我正在寻找一种更简洁的方法，但我想这是不可能的，我在上面计算过。我更感兴趣的是如何创建html操作帮助程序来将信息传递给该方法