c# - 错误: System. Data.SqlClient.SqlException:不允许新事务，因为 session 中有其他线程在运行

Question

我正在尝试单独更新每个产品，其中可以在一个订单中找到多个产品。当我按下提交/更新时，我将 orderid 与新产品数量一起发送到 Controller 。这是我看到的错误:

System.Data.SqlClient.SqlException: New transaction is not allowed because there are other threads running in the session.

这是重定向到表单的 Controller 。

[HttpGet]
    [Authorize(Roles = "ADM")]
    public ActionResult UpdateDetails(Guid id)
    {
        BusinessLayer.Orders blorder = new BusinessLayer.Orders();
        return View(blorder.GetOrderDetailsByOrderId(id));
    }

这是表格。

@model IQueryable<CommonLayer.ORDERDETAIL>
@{
    ViewBag.Title = "UpdateDetails";
    Layout = "~/Views/Shared/_Layout.cshtml";
}

<h2>UpdateDetails</h2>


<table class="table table-striped" style="font-size:medium;">
    <tr>

        <th>
            Order Details ID
        </th>
        <th>
            Price
        </th>
        <th>
            VAT Rate
        </th>
        <th>
            Quantity
        </th>
    </tr>

    @foreach (var item in Model)
    {

            <tr>
                <td>
                    @Html.DisplayFor(modelItem => item.OrderDetailsId)
                </td>
                <td>
                    @Html.DisplayFor(modelItem => item.ProductPrice)
                </td>
                <td>
                    @Html.DisplayFor(modelItem => item.ProductVATRate)
                </td>
                <td>
                    <form action="/order/updatedetails/@item.OrderDetailsId" method="post" enctype="multipart/form-data">
                        <input type="text" name="prodqty" value="@item.ProductQuantity" />
                        <div class="form-group">
                            <div class="col-md-offset-2 col-md-10">
                                <br />
                                <input type="submit" value="Update" class="btn btn-primary" />
                            </div>
                        </div>
                    </form>
                </td>
            </tr>
        }

</table>

这是表单重定向到的 Controller 。

[HttpPost]
    [Authorize(Roles = "ADM")]
    public ActionResult UpdateDetails(Guid id, int prodqty)
    {
        BusinessLayer.Orders blorder = new BusinessLayer.Orders();
        CommonLayer.ORDERDETAIL orderdetail = blorder.GetOrderDetailByDetailId(id);
        blorder.UpdateOrderDetails(orderdetail, prodqty);
        return RedirectToAction("ViewOrder");
    }

这是用于实际更新库存的代码。

public void UpdateOrderDetails(CommonLayer.ORDERDETAIL orderdetail, int prodqty)
    {
            CommonLayer.ORDERDETAIL orderDetails = this.GetOrderDetail(orderdetail.OrderDetailsOrderId);
            CommonLayer.ORDERDETAIL od = new CommonLayer.ORDERDETAIL();
            DataLayer.DAProducts daprod = new DataLayer.DAProducts(this.Entities);
            CommonLayer.PRODUCT product = daprod.GetProduct(orderDetails.OrderDetailsProductId);

            od.OrderDetailsProductId = orderDetails.OrderDetailsProductId;
            od.OrderDetailsId = orderDetails.OrderDetailsId;
            od.OrderDetailsOrderId = orderDetails.OrderDetailsOrderId;
            od.ProductVATRate = orderDetails.ProductVATRate;
            od.ProductPrice = orderDetails.ProductPrice;
            od.ProductQuantity = prodqty;
            if (od.ProductQuantity <= product.ProductQuantity)
            {
                if (od.ProductQuantity > orderDetails.ProductQuantity)
                {
                    product.ProductQuantity -= (od.ProductQuantity - orderDetails.ProductQuantity);
                    daprod.UpdateProduct(product);
                    this.Entities.Entry(orderDetails).CurrentValues.SetValues(od);
                    this.Entities.SaveChanges();
                }
                else if (od.ProductQuantity < orderDetails.ProductQuantity)
                {
                    product.ProductQuantity += (orderDetails.ProductQuantity - od.ProductQuantity);
                    daprod.UpdateProduct(product);
                    this.Entities.Entry(orderDetails).CurrentValues.SetValues(od);
                    this.Entities.SaveChanges();
                }
            }
        else
        {
            throw new Exception("Stock is too low");
        }
    }

这就是在 this.Entities.SaveChanges();

上显示错误的地方

public void UpdateProduct(CommonLayer.PRODUCT product)
    {
        CommonLayer.PRODUCT ExistingProduct = this.GetProduct(product.ProductId);
        this.Entities.Entry(ExistingProduct).CurrentValues.SetValues(product);
        this.Entities.SaveChanges();
    }

我该如何解决这个问题？

Answer 1

哦哦。我认为您过多地重复使用实体。尝试为您使用的每个事务初始化一个新的上下文...执行此操作(同样，从 UpdateProduct 函数中删除 SaveChanges，这样您将只调用 SaveChanges 一次...在你的 if-else-if block 之前尝试这个

using(var context = new CommonLayer.DBModelEntities()){
 if (od.ProductQuantity > orderDetails.ProductQuantity)
 {
   product.ProductQuantity -= (od.ProductQuantity - orderDetails.ProductQuantity);
   daprod.UpdateProduct(product, context);
   context.Entry(orderDetails).CurrentValues.SetValues(od);
 }
 else if (od.ProductQuantity < orderDetails.ProductQuantity)
 {
    product.ProductQuantity += (orderDetails.ProductQuantity - od.ProductQuantity);
    daprod.UpdateProduct(product, context);
    context.Entry(orderDetails).CurrentValues.SetValues(od);
 }

 context.SaveChanges();
}

有了这个，您还应该更改 UpdateProduct 函数以接收您正在使用的当前数据库上下文

public void UpdateProduct(CommonLayer.PRODUCT product, CommonLayer.DBModelEntities context)
{
  CommonLayer.PRODUCT ExistingProduct = this.GetProduct(product.ProductId);
  context.Entry(ExistingProduct).CurrentValues.SetValues(product);
}