Question

这里是我的查询结果和类，我想要列表如何创建“客户”列表对象列表“合同”是属性

customer contract_id number_of_products 
1        HD2         1000 
1        HD3         4500 
1        HD4         20000 
2        HD5         70 
2        HD6         8000
3        HD7         660
3        HD8         2200



    public class customer 
    {
        public string customer { get; set; }
        public List<contract> ls_contract{ get; set; }
    }
    public class contract
    {
        public string contract_id{ get; set; }
        public string number_of_products { get; set; }
    }

Answer 1

首先，您需要遵循C＃编码惯例：

public class Customer 
{
    public string Name { get; set; }
    public List<Contract> Contracts { get; set; }
}

public class Contract
{
    public string Id { get; set; }
    public string NumberOfProducts { get; set; }
}

您需要一些平面数据结构来从。

中读取查询结果

private class CustomerContract 
{
    public string CustomerName { get; set;}
    public string ContractId { get; set;}
    public int NumberOfProducts { get; set;}
}

将结果集读取到该平面数据结构后，您可以按客户ID分组并转换为所需的数据结构。

var result = customerContract.GroupBy(item => item.CustomerName)
                             .Select(group => new Customer {
                                                  Name = group.CustomerName,
                                                  Contracts = group.Select(
                                                       e => new Contract {
                                                           Id = e.ContractId,
                                                           NumberOfProducts = e.NumberOfProducts
                                                       }
                                                  ).ToList()
                                              })
                             .ToList();

Answer 2

您可以创建并填充Customer列表，

List<Customer> lstCustomer = new List<Customer>()
            {
                new Customer(){customer="1", ls_contract=new List<Contract>()
                {
                    new Contract(){contract_id="HD2", number_of_products="1000"},
                    new Contract(){contract_id="HD3", number_of_products="4500"},
                    new Contract(){contract_id="HD4", number_of_products="20000"}
                } },
                new Customer(){customer="2", ls_contract=new List<Contract>()
                {
                    new Contract(){contract_id="HD5", number_of_products="70"},
                    new Contract(){contract_id="HD6", number_of_products="8000"},
                } },
                new Customer(){customer="3", ls_contract=new List<Contract>()
                {
                    new Contract(){contract_id="HD7", number_of_products="660"},
                    new Contract(){contract_id="HD8", number_of_products="2200"},
                } }


            };

从查询结果创建列表对象？

2 个答案: