我有以下類:轉換列表字典
public class Header
{
public int Id { get; set; }
....
}
public class Item
{
public int Id { get; set; }
public int HeaderId { get; set; } //FK
public int ItemSequence { get; set; }
public string Value { get; set; }
...
}
Header
和Item
有一個一對多的關係(每個Header
有很多Items
我有以下Items
:
{{Id=1, HeaderId=1, ItemSequence =1, Value="A"},
{Id=2, HeaderId=1, ItemSequence =2, Value="B"},
{Id=3, HeaderId=2, ItemSequence =1, Value="C"},
{Id=4, HeaderId=2, ItemSequence =2, Value="D"},
{Id=5, HeaderId=2, ItemSequence =3, Value="B"}}
我想寫一個查詢來查找字典,關鍵是每個的第一個(ItemSequence
= 1)和值是其它ItemSequence
的價值觀,在其它字我想達到以下結果:
Key: {HeaderId=1, ItemSequence =1} , Values : {"A","B"}
Key: {HeaderId=2, ItemSequence =1} , Values : {"C","D","B"}
我寫以下查詢:
var result = ctx.Headers
.SelectMany(x => x.Items
.Select(t => new { t.Id,t.ItemSequence,t.HeaderId}))
.?
哪些代碼我應該使用?
?