Linq 按名字姓氏分组并从子数组中进行选择

我正在使用实体框架并对返回一家公司的数据库执行查询，而该公司又有许多联系人。

我有两种情况，我想对具有相同名字和姓氏的"我的联系人"进行分组。

虽然我可以遍历存储结果的新对象数组，但我使用的是实体框架，并且必须多次加载数据会很慢，因此如果可能的话，我更愿意在结果集中按原样维护对象。

计划是我可以遍历结果数组，对 MyContacts 对象进行更改，并将对象更新到 EF 存储库中。

第一种情况是按名称对联系人列表进行分组，但我不确定如何在不创建新的类数据集的情况下进行分组。

第二种情况更复杂，我有一个MyAccounts列表(每个帐户都有一个MyContacts列表(，我想返回所有列表的MyContacts，按名字和姓氏分组，如果可能的话，返回原始类。

非常感谢，克里斯。

我已经删除了数据访问权限，并在下面做了一个简单的例子：

class MyAccount
{
    public string accountName { get; set; }
    public List<MyContact> Contacts { get; set; }
}
class MyContact
{
    public string firstname { get; set; }
    public string lastname  { get; set; }
}
MyContact contactA = new MyContact() { firstname = "Chris", lastname = "b", ID = 100 };
MyContact contactB = new MyContact() { firstname = "Chris", lastname = "b", ID = 101 };
MyContact contactC = new MyContact() { firstname = "Peter", lastname = "Bread", ID = 102 };
MyContact contactD = new MyContact() { firstname = "James", lastname = "apple", ID = 103 };
MyContact contactE = new MyContact() { firstname = "Richard", lastname = "Brian", ID = 104 };
MyContact contactF = new MyContact() { firstname = "James", lastname = "apple", ID = 105 };
List<MyContact> contacts = new List<MyContact>();
contacts.AddRange(new MyContact[] { contactA, contactB, contactC, contactD, contactE, contactF } );
// how do i get a list of items, grouped by same first and lastname?
MyAccount companyA = new MyAccount() { accountName = "CompanyA", Contacts = new List<MyContact>() };
companyA.Contacts.AddRange(new MyContact[] { contactA, contactB, contactC });
MyAccount companyB = new MyAccount() { accountName = "CompanyB", Contacts = new List<MyContact>() };
companyB.Contacts.AddRange(new MyContact[] { contactA, contactB, contactC });
MyAccount companyC = new MyAccount() { accountName = "CompanyB", Contacts = new List<MyContact>() };
companyB.Contacts.AddRange(new MyContact[] { contactA, contactB, contactC, contactD, contactE });
List<MyAccount> companyList = new List<MyAccount>(new MyAccount[] { companyA, companyB, companyC });
// from the companyList, is there any way to get a list of MyContact types grouped by duplicate first and lastname?

    var result = from c in contacts
                 group c by new { c.firstname, c.lastname } into g
                 select g.ToList();
    var result1 = from c in companyList.SelectMany(company => company.Contacts)
                  group c by new { c.firstname, c.lastname } into g
                  select g.ToList();