C# lambda表达式的实体框架组不工作？

我在.NETMVC上工作了好几天。我想显示一个表，在这个表中，我向视图发送一些列和分组的总和。我面临的问题是=>行动

    public ActionResult Index()
    {
        TempData["UserDetails"] = db.UserDetails.Include(x => x.User).ToList();
        var financeofstudents = db.Financeofstudents.Include(f => f.Batche).Include(f => f.User).GroupBy(x => x.UserId).Select(x => new 
        {
            debit = x.Sum(item => item.debit),
            credit = x.Sum(item => item.credit),
            balance = x.Sum(item => item.balance)
        }).ToList();
        return View(financeofstudents);
    }

耶！也许它的工作很好，但我不知道。因为我在客户端遇到了几个错误

当我只是在客户端发送一个列表及其工作文件时。like=>

var financeofstudents = db.Financeofstudents.Include(f => f.Batche).Include(f => f.User).ToList();

但是当我使用这个=>时，因为我需要一个group by==>

        var financeofstudents = db.Financeofstudents.Include(f => f.Batche).Include(f => f.User).GroupBy(x => x.UserId).Select(x => new 
        {
            debit = x.Sum(item => item.debit),
            credit = x.Sum(item => item.credit),
            balance = x.Sum(item => item.balance)
        }).ToList();

我得到的错误是=>

而我的观点=>

        @using TSMS_Atp_2_Final_Project.Models.Com.Tsms
        @model IEnumerable<Financeofstudent>

        @{
            ViewBag.Title = "Finance";
            IEnumerable<UserDetail> UserDetailsTable = TempData["UserDetails"] as IEnumerable<UserDetail>;    
        }

        <h2>Available Finance Detail Of Students...</h2>

        <p>
            <a href="@Url.Action("ASIB", "Batche")" class="btn btn-primary btn-sm">Assign New</a>
        </p>
        <div class="table-responsive">
            <table class="table table-striped table-inverse table-bordered">
                <tr>
                    <th>
                        @Html.DisplayNameFor(model => model.Batche.batch_code)
                    </th>
                    <th>
                        @Html.DisplayNameFor(model => model.Batche.name)
                    </th>
                    <th>
                        @Html.DisplayNameFor(model => model.User.UserId)
                    </th>
                    <th>
                        @Html.Label("Full Name")
                    </th>
                    <th>
                        @Html.DisplayNameFor(model => model.debit)
                    </th>
                    <th>
                        @Html.DisplayNameFor(model => model.credit)
                    </th>
                    <th>
                        @Html.DisplayNameFor(model => model.balance)
                    </th>
                    <th>
                        @Html.DisplayNameFor(model => model.lastTrunsaction)
                    </th>
                    <th></th>
                </tr>

                @foreach (var item in Model)
                {
                    <tr>
                        <td>
                            @Html.ActionLink(item.Batche.batch_code, "Details", "Batche", new { id = item.Batche.batch_code }, null)
                        </td>
                        <td>
                            @Html.ActionLink(item.Batche.name, "Details", "Course", new { id = item.Batche.name }, null)
                        </td>
                        <td>
                            @Html.DisplayFor(modelItem => item.User.UserId)
                        </td>
                        <td>
                            @{
                                var UserDetailsId = UserDetailsTable.Where(x => x.UserId == item.User.UserId).Select(x => x.id).FirstOrDefault();
                                var FullName = UserDetailsTable.Where(x => x.UserId == item.User.UserId).Select(x => x.fullname).FirstOrDefault();
                            }
                            @Html.ActionLink(FullName, "Details", "Students", new { id = UserDetailsId }, null)
                        </td>
                        <td>
                            @Html.DisplayFor(modelItem => item.debit)
                        </td>
                        <td>
                            @Html.DisplayFor(modelItem => item.credit)
                        </td>
                        <td>
                            @Html.DisplayFor(modelItem => item.balance)
                        </td>
                        <td>
                            @Html.DisplayFor(modelItem => item.lastTrunsaction)
                        </td>
                        <td>
                            <div style="width:80px;">
                                @Html.ActionLink("Edit", "Edit", new { id = item.id }) |
                                @Html.ActionLink("Details", "Details", new { id = item.id }) |
                                @Html.ActionLink("Delete", "Delete", new { id = item.id })
                            </div>
                        </td>
                    </tr>
                }
            </table>
        </div>

---

在客户端，如上表所示？请帮助我。我该如何解决我的问题。或者我做错了什么。或者有其他方法可以获得我想要的输出。

您的group by只返回3个整数的列表。该列表是passend，因为它们是您视图的模型。您无权访问任何数据库对象属性

基本上，执行的SQL只获取3个和的列表…

看看下面的代码：

.Select(x => new 
    {
        debit = x.Sum(item => item.debit),
        credit = x.Sum(item => item.credit),
        balance = x.Sum(item => item.balance)
    }).ToList();

它返回匿名类型，但您的视图使用IEnumerable模型

尝试这样做：

创建类FinanceofstudentModel

class FinanceofstudentsModel
{
    public string UserId { get; set; }
    public int Debit { get; set; }
    public int Credit { get; set; }
    public int Balance { get; set; }
}

然后将您的选择更改为类似以下内容

var financeofstudents = db.Financeofstudents
                          .Include(f => f.Batche)
                          .Include(f => f.User)
                          .GroupBy(x => x.UserId)
                          .Select(x => new FinanceofstudentsModel()
                                      {
                                          UserId = x.Key,
                                          Debit = x.Sum(item => item.debit),
                                          Credit = x.Sum(item => item.credit),
                                          Balance = x.Sum(item => item.balance)
                                      });

在您的视图中使用此模型

@model IEnumerable<FinanceofstudentModel>

您的视图可能如下所示：

@model IEnumerable<FinanceofstudentModel>
@foreach (var fm in Model)
{
    <p>User: @fm.UserId Debit: @fm.Debit Credit: @fm.Credit Balance: @fm.Balance</p>
    <hr/>
}

因此，重要的是，您的模型只有4个属性UserId、Debit、Credit和Balance。若你们想添加额外的属性，你们应该在FinanceofstudentModel中添加它并填写controller

我希望这能帮助您创建一个类：

public class StudentFinance
{
    public double debit { get; set; }
    public double credit { get; set; }
    public double balance { get; set; }
}

将LINQ查询更改为

        var financeofstudents = db.Financeofstudents.Include(f => f.Batche).Include(f => f.User).GroupBy(x => x.UserId).Select(x => new StudentFinance
        {
            debit = x.Sum(item => item.debit),
            credit = x.Sum(item => item.credit),
            balance = x.Sum(item => item.balance)
        }).ToList();

最后，将视图上的模型更改为：

@model IEnumerable<StudentFinance>

---

那应该行得通。。如果这解决了您的问题，请标记已回答。

您正在创建匿名对象的集合，并将其传递给需要Financeofstudent集合的视图-它们需要是相同的类型。创建一个视图模型，其中包含您想要在视图中使用的属性。选择X=>new yourViewModel{…，然后在视图中使用该视图模型

@model IEnumerable<FinanceofstudentModel>
@foreach (var fm in Model)
{
    <p>User: @fm.UserId Debit: @fm.Debit Credit: @fm.Credit Balance: @fm.Balance</p>
    <hr/>
}

public class StudentFinance
{
    public double debit { get; set; }
    public double credit { get; set; }
    public double balance { get; set; }
}

        var financeofstudents = db.Financeofstudents.Include(f => f.Batche).Include(f => f.User).GroupBy(x => x.UserId).Select(x => new StudentFinance
        {
            debit = x.Sum(item => item.debit),
            credit = x.Sum(item => item.credit),
            balance = x.Sum(item => item.balance)
        }).ToList();

@model IEnumerable<StudentFinance>