Linq投影将列表平整为已定义字符串
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我正在尝试合并并用逗号分隔（或空格）一个列表并对其进行投影。我下面有一些示例代码。
public class Friend
{
public string Name { get; set; }
}
public class Person
{
public int PersonID { get; set; }
public string FirstName { get; set; }
public string Surname { get; set; }
List<Friend> Friends { get; set; }
}
public class ProjectedPerson
{
public int PersonID { get; set; }
public string FirstName { get; set; }
public string Surname { get; set; }
public string FriendsList { get; set; }
}
public class Test
{
public void MyTest()
{
var query = from p in MyDataStore.Person
select p;
var results = from q in query
select new ProjectedPerson
{
PersonID = q.PersonID,
FirstName = q.FirstName,
Surname = q.Surname,
FriendsList = q.FriendsList.Concat() //??? How can I concat this and return a string
};
}
}
没有找到相关结果
已邀请:
2 个回复
宠封钞轰
var query = (from p in MyDataStore.Person select p).ToList(); // <-- bring into memory with ToList() var results = from q in query select new ProjectedPerson { PersonID = q.PersonID, FirstName = q.FirstName, Surname = q.Surname, FriendsList = q.Friends.Aggregate<Friend, string>(null, (accum, f) => accum + (accum == null ? accum : \", \") + f.Name) };刷遍派戳
var query = (from p in MyDataStore.Person select p).ToList(); // <-- bring into memory with ToList() var results = from q in query select new ProjectedPerson { PersonID = q.PersonID, FirstName = q.FirstName, Surname = q.Surname, FriendsList = string.Join( \", \", q.Friends.Select( f => f.Name ) ) };