C# MVC核心存储库一次查询所有数据

我们有一个客户事务表，其中包含多个带外键的查找表。我们希望看到3张桌子连接在一起

public class CustomerTransaction
{
    public int CustomerTransactionId{ get; set; },
    public int ProductTypeId {get; set; }, //joins to ProductTypeTable
    public int StatusID {get; set; },  //joins to StatusTypeTable
    public string DateOfPurchase{ get; set; },
    public int PurchaseAmount { get; set; },
}

public class ProductType
{
    public int ProductTypeId{ get; set; }
    public string ProductName { get; set; },
    public string ProductDescription { get; set; },
}

public class StatusType
{
    public int StatusId{ get; set; }
    public string StatusName{ get; set; },
    public string Description{ get; set; },

}

我如何确保服务电话一个接一个？我不想获取所有不必要的客户事务，然后在内存中进行过滤。我想进行一次服务调用，以在一次sql查询中查找>50的客户事务

public class CustomerTransaction
{
    public int CustomerTransactionId{ get; set; },
    public int ProductTypeId {get; set; }, //joins to ProductTypeTable
    public int StatusID {get; set; },  //joins to StatusTypeTable
    public string DateOfPurchase{ get; set; },
    public int PurchaseAmount { get; set; },
}

public class ProductType
{
    public int ProductTypeId{ get; set; }
    public string ProductName { get; set; },
    public string ProductDescription { get; set; },
}

public class StatusType
{
    public int StatusId{ get; set; }
    public string StatusName{ get; set; },
    public string Description{ get; set; },

}

存储库：

CustomerTransaction GetTransactionbyCustomerId(int customerid)
{
   var result = ct.CustomerTransaction.Where(x => x.CustomerTransactionId == customerid).ToList()
   return result;
}

void GetByCustomerTransactionGreaterthan50(int id)
{
   var newdata = CustomerTransaction.GetByCustomerTransactionId();
   nt.newdata.Where(x => x.PurchaseAmount > 50).ToList()
   return newdata;
}

public class CustomerTransaction
{
    public int CustomerTransactionId{ get; set; },
    public int ProductTypeId {get; set; }, //joins to ProductTypeTable
    public int StatusID {get; set; },  //joins to StatusTypeTable
    public string DateOfPurchase{ get; set; },
    public int PurchaseAmount { get; set; },
}

public class ProductType
{
    public int ProductTypeId{ get; set; }
    public string ProductName { get; set; },
    public string ProductDescription { get; set; },
}

public class StatusType
{
    public int StatusId{ get; set; }
    public string StatusName{ get; set; },
    public string Description{ get; set; },

}

服务电话：

CustomerTransaction GetTransactionbyCustomerId(int customerid)
{
   var result = ct.CustomerTransaction.Where(x => x.CustomerTransactionId == customerid).ToList()
   return result;
}

void GetByCustomerTransactionGreaterthan50(int id)
{
   var newdata = CustomerTransaction.GetByCustomerTransactionId();
   nt.newdata.Where(x => x.PurchaseAmount > 50).ToList()
   return newdata;
}

public class CustomerTransaction
{
    public int CustomerTransactionId{ get; set; },
    public int ProductTypeId {get; set; }, //joins to ProductTypeTable
    public int StatusID {get; set; },  //joins to StatusTypeTable
    public string DateOfPurchase{ get; set; },
    public int PurchaseAmount { get; set; },
}

public class ProductType
{
    public int ProductTypeId{ get; set; }
    public string ProductName { get; set; },
    public string ProductDescription { get; set; },
}

public class StatusType
{
    public int StatusId{ get; set; }
    public string StatusName{ get; set; },
    public string Description{ get; set; },

}

型号：

public class CustomerTransaction
{
    public int CustomerTransactionId{ get; set; },
    public int ProductTypeId {get; set; }, //joins to ProductTypeTable
    public int StatusID {get; set; },  //joins to StatusTypeTable
    public string DateOfPurchase{ get; set; },
    public int PurchaseAmount { get; set; },
}

public class ProductType
{
    public int ProductTypeId{ get; set; }
    public string ProductName { get; set; },
    public string ProductDescription { get; set; },
}

public class StatusType
{
    public int StatusId{ get; set; }
    public string StatusName{ get; set; },
    public string Description{ get; set; },

}

---

您可以在

ToList（）

之前进行

Select

projection，这将确保EF生成的sql语句也只包含您要投影的字段

public class CustomerTransaction
{
    public int CustomerTransactionId{ get; set; },
    public int ProductTypeId {get; set; }, //joins to ProductTypeTable
    public int StatusID {get; set; },  //joins to StatusTypeTable
    public string DateOfPurchase{ get; set; },
    public int PurchaseAmount { get; set; },
}

public class ProductType
{
    public int ProductTypeId{ get; set; }
    public string ProductName { get; set; },
    public string ProductDescription { get; set; },
}

public class StatusType
{
    public int StatusId{ get; set; }
    public string StatusName{ get; set; },
    public string Description{ get; set; },

}

比如：

public class CustomerTransaction
{
    public int CustomerTransactionId{ get; set; },
    public int ProductTypeId {get; set; }, //joins to ProductTypeTable
    public int StatusID {get; set; },  //joins to StatusTypeTable
    public string DateOfPurchase{ get; set; },
    public int PurchaseAmount { get; set; },
}

public class ProductType
{
    public int ProductTypeId{ get; set; }
    public string ProductName { get; set; },
    public string ProductDescription { get; set; },
}

public class StatusType
{
    public int StatusId{ get; set; }
    public string StatusName{ get; set; },
    public string Description{ get; set; },

}

var result = ct.CustomerTransaction.Where(x => x.CustomerTransactionId == customerid).Select(x=> new CustomerTransaction()).ToList()

要进行筛选，您可以在where条件中包括筛选：

public class CustomerTransaction
{
    public int CustomerTransactionId{ get; set; },
    public int ProductTypeId {get; set; }, //joins to ProductTypeTable
    public int StatusID {get; set; },  //joins to StatusTypeTable
    public string DateOfPurchase{ get; set; },
    public int PurchaseAmount { get; set; },
}

public class ProductType
{
    public int ProductTypeId{ get; set; }
    public string ProductName { get; set; },
    public string ProductDescription { get; set; },
}

public class StatusType
{
    public int StatusId{ get; set; }
    public string StatusName{ get; set; },
    public string Description{ get; set; },

}

ct.CustomerTransaction.Where(x => x.CustomerTransactionId == customerid && x.PurchaseAmount > 50)

---

或者让您的GetTransactionbyCustomerId像在服务调用中一样返回查询和筛选

选项1

public class CustomerTransaction
{
    public int CustomerTransactionId{ get; set; },
    public int ProductTypeId {get; set; }, //joins to ProductTypeTable
    public int StatusID {get; set; },  //joins to StatusTypeTable
    public string DateOfPurchase{ get; set; },
    public int PurchaseAmount { get; set; },
}

public class ProductType
{
    public int ProductTypeId{ get; set; }
    public string ProductName { get; set; },
    public string ProductDescription { get; set; },
}

public class StatusType
{
    public int StatusId{ get; set; }
    public string StatusName{ get; set; },
    public string Description{ get; set; },

}

您需要调整存储库，以便能够在服务层中添加查询：

public class CustomerTransaction
{
    public int CustomerTransactionId{ get; set; },
    public int ProductTypeId {get; set; }, //joins to ProductTypeTable
    public int StatusID {get; set; },  //joins to StatusTypeTable
    public string DateOfPurchase{ get; set; },
    public int PurchaseAmount { get; set; },
}

public class ProductType
{
    public int ProductTypeId{ get; set; }
    public string ProductName { get; set; },
    public string ProductDescription { get; set; },
}

public class StatusType
{
    public int StatusId{ get; set; }
    public string StatusName{ get; set; },
    public string Description{ get; set; },

}

存储库：

public class CustomerTransaction
{
    public int CustomerTransactionId{ get; set; },
    public int ProductTypeId {get; set; }, //joins to ProductTypeTable
    public int StatusID {get; set; },  //joins to StatusTypeTable
    public string DateOfPurchase{ get; set; },
    public int PurchaseAmount { get; set; },
}

public class ProductType
{
    public int ProductTypeId{ get; set; }
    public string ProductName { get; set; },
    public string ProductDescription { get; set; },
}

public class StatusType
{
    public int StatusId{ get; set; }
    public string StatusName{ get; set; },
    public string Description{ get; set; },

}

IQueryable<CustomerTransaction> QueryTransactionbyCustomerId(int customerid)
{
   var result = ct.CustomerTransaction.Where(x => x.CustomerTransactionId == customerid);
   return result;
}

List<CustomerTransaction> GetTransactionByCustomerIdAndAmount(int customerid, int amount)
{
   var result = ct.CustomerTransaction.Where(x => x.CustomerTransactionId == customerid && x.PurchaseAmount > amount).ToList()
   return result;
}

IQueryTableQueryTransactionByCustomerId（int-customerid）
{
var result=ct.CustomerTransaction.Where（x=>x.CustomerTransactionId==customerid）；
返回结果；
}

选项2

public class CustomerTransaction
{
    public int CustomerTransactionId{ get; set; },
    public int ProductTypeId {get; set; }, //joins to ProductTypeTable
    public int StatusID {get; set; },  //joins to StatusTypeTable
    public string DateOfPurchase{ get; set; },
    public int PurchaseAmount { get; set; },
}

public class ProductType
{
    public int ProductTypeId{ get; set; }
    public string ProductName { get; set; },
    public string ProductDescription { get; set; },
}

public class StatusType
{
    public int StatusId{ get; set; }
    public string StatusName{ get; set; },
    public string Description{ get; set; },

}

或在数据访问层中创建另一种方法：

public class CustomerTransaction
{
    public int CustomerTransactionId{ get; set; },
    public int ProductTypeId {get; set; }, //joins to ProductTypeTable
    public int StatusID {get; set; },  //joins to StatusTypeTable
    public string DateOfPurchase{ get; set; },
    public int PurchaseAmount { get; set; },
}

public class ProductType
{
    public int ProductTypeId{ get; set; }
    public string ProductName { get; set; },
    public string ProductDescription { get; set; },
}

public class StatusType
{
    public int StatusId{ get; set; }
    public string StatusName{ get; set; },
    public string Description{ get; set; },

}

存储库：

public class CustomerTransaction
{
    public int CustomerTransactionId{ get; set; },
    public int ProductTypeId {get; set; }, //joins to ProductTypeTable
    public int StatusID {get; set; },  //joins to StatusTypeTable
    public string DateOfPurchase{ get; set; },
    public int PurchaseAmount { get; set; },
}

public class ProductType
{
    public int ProductTypeId{ get; set; }
    public string ProductName { get; set; },
    public string ProductDescription { get; set; },
}

public class StatusType
{
    public int StatusId{ get; set; }
    public string StatusName{ get; set; },
    public string Description{ get; set; },

}

IQueryable<CustomerTransaction> QueryTransactionbyCustomerId(int customerid)
{
   var result = ct.CustomerTransaction.Where(x => x.CustomerTransactionId == customerid);
   return result;
}

List<CustomerTransaction> GetTransactionByCustomerIdAndAmount(int customerid, int amount)
{
   var result = ct.CustomerTransaction.Where(x => x.CustomerTransactionId == customerid && x.PurchaseAmount > amount).ToList()
   return result;
}

List getTransactionByCustomerId和amount（int-customerid，int-amount）
{
var result=ct.CustomerTransaction.Where（x=>x.CustomerTransactionId==customerid&&x.PurchaseAmount>amount）.ToList（）
返回结果；
}

---

根据您的体系结构，您应该选择以下选项之一。

var result=ct.CustomerTransaction.Where（x=>x.CustomerTransactionId==customerid）.ToList（）-这将实现您的查询。您需要在此处返回IQueryable，并仅在服务调用中调用一次toList，不要尝试在“service”方法中筛选数据库行。在数据访问中这样做method@BlueLamp82不过，您没有创建通用存储库，而是在加载数据后尝试对其进行筛选。上下文确实提供了“通用”存储库所提供的功能。ViewModels是为*视图服务的，而不是为存储库服务的。@BlueLamp82是的，您可以而且应该拥有适合您的用例的尽可能多的DTO，而不是试图将一个大实体对象硬塞进所有角色中。如果需要仅从多个实体中选择5个属性，则应仅使用这5个属性创建一个DTO，而不是加载整个对象图。这是分离不同层和用例的唯一方法。您可以使用AutoMapper将实体映射到DTO到ViewModels，以确保如果实体映射失败，视图不会中断changes@BlueLamp82不要。这是IQueryable的工作。把它放在数据访问方法中。从该方法返回IQueryable如果您想应用额外的过滤器并延迟查询的执行，OP实际上会询问如何读取金额大于50的事务。这个问题的措辞很糟糕，被否决的人可能根本没有读过这个问题？这是一个措辞糟糕的问题。你不认为OP第一次是在寻找

包含
吗？@PanagiotisKanavos谢谢，我也很困惑，但我留下我的答案，这可能会对OP有所帮助，让我们看看他会如何评论，让它更清楚。这要视情况而定。如果您公开IQueryable，您将有机会在另一层中添加到该查询中，但滥用这种行为是一种不好的做法。如果您选择选项2，您必须实现许多方法，并且您的存储库将根据您的域而增长。@BlueLamp82您所尝试的操作将确保您将在所有地方重复代码。使用
IQueryable
意味着您不必这样做，只需对现有查询应用
.Where（）
。另外，您试图在错误的级别应用数据访问约束
GetByCustomerTransactionGreater50
首先不应位于业务/服务层。@BlueLamp82如果要应用动态筛选条件并且不想将IQueryable返回到业务层，请向DAL传递一个默认值为null的
Func
参数。如果参数不为null，请将其作为参数传递给
。Where（）
call@BlueLamp82数据层。内部
GetTransactionbyCustomerId
。您可以在查询中根据需要链接任意多个
.Where（）
调用。将条件lambda作为
Func
参数传递。如果它不为null，则在调用
ToList（）
之前添加另一个
.Where（）
，例如
var query=ct.Transactions.Where（x=>CustomerId==a）；if（filter！=null）query=query.Where（filter）
public class CustomerTransaction
{
    public int CustomerTransactionId{ get; set; },
    public int ProductTypeId {get; set; }, //joins to ProductTypeTable
    public int StatusID {get; set; },  //joins to StatusTypeTable
    public string DateOfPurchase{ get; set; },
    public int PurchaseAmount { get; set; },
}

public class ProductType
{
    public int ProductTypeId{ get; set; }
    public string ProductName { get; set; },
    public string ProductDescription { get; set; },
}

public class StatusType
{
    public int StatusId{ get; set; }
    public string StatusName{ get; set; },
    public string Description{ get; set; },

}