C# linq lambda 连接和选择语法

Question

我正在寻找 Msql 查询的对应物:

SELECT per.*,add.addressDescription FROM Persons per 
       JOIN Address add ON per.AddressId = add.AddressId

我有这个问题:

    var query = persons.JOIN(address,per = person.addressId,add = addressId
    (per,add) => 
    new Persons{
                addressDescription = add.addressDescription,
                PersonId = per.PersonId,
                PersonFirstName = per.PersonFirstName
                PersonLastName = per.PersonLastName})

有没有办法在不单独分配 Persons 的其他属性的情况下填充 Persons.addressDescription？想象一下，如果 Persons 还有 10 个属性。

我想避免使用像这样的循环:

foreach(Person person in PersonList)
{
  foreach(Address address in AddressList)
  {
     if(person.addressId == address.addressId){
        person.addressDescription = address.addressDescription
     }
   }
}

Answer 1

var query = persons.join(address,
    per = person.addressId,
    add = addressId
    (per,add) => 
    {
        per.addressDescription = add.addressDescription;
        return per;
    });